IP Subnet Calculator

This calculator returns a variety of information regarding Internet Protocol version 4 (IPv4) and IPv6 subnets including possible network addresses, usable host ranges, subnet mask, and IP class, among others.

IPv4 Subnet Calculator

Ipv6 subnet calculator.

Related Bandwidth Calculator | Binary Calculator

A subnet is a division of an IP network (internet protocol suite), where an IP network is a set of communications protocols used on the Internet and other similar networks. It is commonly known as TCP/IP (Transmission Control Protocol/Internet Protocol).

The act of dividing a network into at least two separate networks is called subnetting, and routers are devices that allow traffic exchange between subnetworks, serving as a physical boundary. IPv4 is the most common network addressing architecture used, though the use of IPv6 has been growing since 2006.

An IP address is comprised of a network number (routing prefix) and a rest field (host identifier). A rest field is an identifier that is specific to a given host or network interface. A routing prefix is often expressed using Classless Inter-Domain Routing (CIDR) notation for both IPv4 and IPv6. CIDR is a method used to create unique identifiers for networks, as well as individual devices. For IPv4, networks can also be characterized using a subnet mask, which is sometimes expressed in dot-decimal notation, as shown in the "Subnet" field in the calculator. All hosts on a subnetwork have the same network prefix, unlike the host identifier, which is a unique local identification. In IPv4, these subnet masks are used to differentiate the network number and host identifier. In IPv6, the network prefix performs a similar function as the subnet mask in IPv4, with the prefix length representing the number of bits in the address.

Prior to the introduction of CIDR, IPv4 network prefixes could be directly obtained from the IP address based on the class (A, B, or C, which vary based on the range of IP addresses they include) of the address and the network mask. Since the introduction of CIDRs, however, assigning an IP address to a network interface requires both an address and its network mask.

Below is a table providing typical subnets for IPv4.

Subnet Cheat Sheet – 24 Subnet Mask, 30, 26, 27, 29, and other IP Address CIDR Network References

As a developer or network engineer, you may need to occasionally look up subnet mask values and figure out what they mean.

To make your life easier, the freeCodeCamp community has made this simple cheat sheet. Just scroll or use Ctrl/Cmd + f to find the value you're looking for.

Here are the charts, followed by some explanations of what they mean.

* /31 is a special case detailed in RFC 3021 where networks with this type of subnet mask can assign two IP addresses as a point-to-point link.

And here's a table of the decimal to binary conversions for subnet mask and wildcard octets:

Note that the wildcard is just the inverse of the subnet mask.

If you are new to network engineering, you can get a better idea of how computer networks work here .

Finally, this cheat sheet and the rest of the article is focused on IPv4 addresses, not the newer IPv6 protocol. If you'd like to learn more about IPv6, check out the article on computer networks above.

How Do IP Address Blocks Work?

IPv4 addresses like 192.168.0.1 are really just decimal representations of four binary blocks.

Each block is 8 bits, and represents numbers from 0-255. Because the blocks are groups of 8 bits, each block is known as an octet . And since there are four blocks of 8 bits, every IPv4 address is 32 bits.

For example, here's what the IP address 172.16.254.1 looks like in binary:

1125px-Ipv4_address

To convert an IP address between its decimal and binary forms, you can use this chart:

The chart above represents one 8 bit octive.

Now lets say you want to convert the IP address 168.210.225.206 . All you need to do is break the address into four blocks ( 168 , 210 , 225 , and 206 ), and convert each into binary using the chart above.

Remember that in binary, 1 is the equivalent to "on" and 0 is "off". So to convert the first block, 168 , into binary, just start from the beginning of the chart and place a 1 or 0 in that cell until you get a sum of 168 .

For example:

128 + 32 + 8 = 168, which in binary is 10101000 .

If you do this for the rest of the blocks, you'd get 10101000.11010010.11100001.11001110 .

What is Subnetting?

If you look at the table above, it can seem like the number of IP addresses is practically unlimited. After all, there are almost 4.2 billion possible IPv4 addresses available.

But if you think about how much the internet has grown, and how many more devices are connected these days, it might not surprise you to hear that there's already a shortage of IPv4 addresses .

Because the shortage was recognized years ago, developers came up with a way to split up an IP address into smaller networks called subnets.

This process, called subnetting, uses the host section of the IP address to break it down into those smaller networks or subnets.

Generally, an IP address is made up of network bits and host bits:

network-and-host-bits

So generally, subnetting does two things: it gives us a way to break up networks into subnets, and allows devices to determine whether another device/IP address is on the same local network or not.

A good way to think about subnetting is to picture your wireless network at home.

Without subnetting, every internet connected device would need its own unique IP address.

But since you have a wireless router, you just need one IP address for your router. This public or external IP address is usually handled automatically, and is assigned by your internet service provider (ISP).

Then every device connected to that router has its own private or internal IP address:

home-network-diagram

Now if your device with the internal IP address 192.168.1.101 wants to communicate with another device, it'll use the IP address of the other device and the subnet mask.

The combination of the IP addresses and subnet mask allows the device at 192.168.1.101 to figure out if the other device is on the same network (like the device at 192.168.1.103 ), or on a completely different network somewhere else online.

Interestingly, the external IP address assigned to your router by your ISP is probably part of a subnet, which might include many other IP addresses for nearby homes or businesses. And just like internal IP addresses, it also needs a subnet mask to work.

How Subnet Masks Work

Subnet masks function as a sort of filter for an IP address. With a subnet mask, devices can look at an IP address, and figure out which parts are the network bits and which are the host bits.

Then using those things, it can figure out the best way for those devices to communicate.

If you've poked around the network settings on your router or computer, you've likely seen this number: 255.255.255.0 .

If so, you've seen a very common subnet mask for simple home networks.

Like IPv4 addresses, subnet masks are 32 bits. And just like converting an IP address into binary, you can do the same thing with a subnet mask.

For example, here's our chart from earlier:

Now let's convert the first octet, 255:

Pretty simple, right? So any octet that's 255 is just 11111111 in binary. This means that 255.255.255.0 is really 11111111.11111111.11111111.00000000 in binary.

Now let's look at a subnet mask and IP address together and calculate which parts of the IP address are the network bits and host bits.

Here are the two in both decimal and binary:

With the two laid out like this, it's easy to separate 192.168.0.101 into network bits and host bits.

Whenever a bit in a binary subnet mask is 1, then the same bit in a binary IP address is part of the network, not the host.

Since the octet 255 is 11111111 in binary, that whole octet in the IP address is part of the network. So the first three octets, 192.168.0 , is the network portion of the IP address, and 101 is the host portion.

In other words, if the device at 192.168.0.101 wants to communicate with another device, using the subnet mask it knows that anything with the IP address 192.168.0.xxx is on the same local network.

Another way to express this is with a network ID, which is just the network portion of the IP address. So the network ID of the address 192.168.0.101 with a subnet mask of 255.255.255.0 is 192.168.0.0 .

And it's the same for the other devices on the local network ( 192.168.0.102 , 192.168.0.103 , and so on).

What Does CIDR Mean and What is CIDR Notation?

CIDR stands for Classless Inter-Domain Routing, and is used in IPv4, and more recently, IPv6 routing.

CIDR was introduced in 1993 as a way to slow the usage of IPv4 addresses, which were quickly being exhausted under the older Classful IP addressing system that the internet was first built on.

CIDR encompasses a couple of major concepts.

The first is Variable Length Submasking (VLSM), which basically allowed network engineers to create subnets within subnets. And those subnets could be different sizes, so there would be fewer unused IP addresses.

The second major concept CIDR introduced is CIDR notation.

CIDR notation is really just shorthand for the subnet mask, and represents the number of bits available to the IP address. For instance, the /24 in 192.168.0.101/24 is equivalent to the IP address 192.168.0.101 and the subnet mask 255.255.255.0 .

How to Calculate CIDR Noation

To figure out the CIDR notation for a given subnet mask, all you need to do is convert the subnet mask into binary, then count the number of ones or "on" digits. For example:

Because there's three octets of ones, there are 24 "on" bits meaning that the CIDR notation is /24 .

You can write it either way, but I'm sure you'll agree that /24 is a whole lot easier to write than 255.255.255.0 .

This is usually done with an IP address, so let's take a look at the same subnet mask with an IP address:

The first three octets of the subnet mask are all "on" bits, so that means that the same three octets in the IP address are all network bits.

Let's take a look at the last forth octet in a bit more detail:

In this case, because all the bits for this octet in the subnet mask are "off", we can be certain that all of the corresponding bits for this octet in the IP address are part of the host.

When you write CIDR notation it's usually done with the network ID. So the CIDR notation of the IP address 192.168.0.101 with a subnet mask of 255.255.255.0 is 192.168.0.0/24 .

To see more examples of how to calculate the CIDR notation and network ID for a given IP address and subnet mask, check out this video:

Classful IP Addressing

Now that we've gone over some basic examples of subnetting and CIDR, let's zoom out and look at what's known as Classful IP addressing.

Back before subnetting was developed, all IP addresses fell into a particular class:

subnetting

Note that there are class D and E IP addresses, but we'll go into these in more detail a bit later.

Classful IP addresses gave network engineers a way to provide different organizations with a range of valid IP addresses.

There were a lot of issues with this approach that eventually lead to subnetting. But before we get into those, let's take a closer look at the different classes.

Class A IP Addresses

For Class A IP addresses,  the first octet (8 bits / 1 byte) represent the network ID, and the remaining three octets (24 bits / 3 bytes) are the host ID.

Class A IP addresses range from 1.0.0.0 to 127.255.255.255 , with a default mask of 255.0.0.0 (or /8 in CIDR).

This means that Class A addressing can have a total of 128 (2 7 ) networks and 16,777,214 (2 24 -2) usable addresses per network.

Also, note that the range 127.0.0.0 to 127.255.255.255 within the Class A range is reserved for host loopback address (see RFC5735 ).

Class B IP Addresses

For Class B IP addresses, the first two octets (16 bits / 2 bytes) represent the network ID and the remaining two octets (16 bits / 2 bytes) are the host ID.

Class B IP addresses range from 128.0.0.0 to 191.255.255.255 , with a default subnet mask of 255.255.0.0 (or /16 in CIDR).

Class B addressing can have 16,384 (2 14 ) network addresses and 65,534 (2 16 ) usable addresses per network.

Class C IP Addresses

For Class C IP addresses, the first three octets (24 bits / 3 bytes) represent the network ID and the last octet (8 bits / 1 bytes) is the host ID.

Class C IP Addresses range from 192.0.0.0 to 223.255.255.255 , with a default subnet mask of 255.255.255.0 (or /24 in CIDR).

Class C translates to 2,097,152 (2 21 ) networks and 254 (2 8 -2) usable addresses per network.

Class D and Class E IP Addresses

The last two classes are Class D and Class E.

Class D IP addresses are reserved for multicasts. They occupy the range from 224.0.0.0 through 239.255.255.255 .

Class E IP addresses are experimental, and are anything over 240.0.0.0 .

The Issue with Classful IP Addresses

The main issue with classful IP addresses is that it wasn't efficient, and could lead to a lot of wasted IP addresses.

For example, imagine that you're part of a large organization back then. Your company has 1,000 employees, meaning that it would fall into class B.

But if you look above, you'll see that a class B network can support up to 65,534 usable addresses. That's way more than your organization would likely need, even if each employee had multiple devices with a unique address.

And there was no way your organization could fall back to class C – there just wouldn't be enough usable IP addresses.

So while classful IP addresses were used around the time IPv4 addresses became widespread, it quickly became clear that a better system would be necessary to ensure we wouldn't use up all of the ~4.2 billion usable addresses.

Classful IP addresses haven't been used since they were replaced by CIDR in 1993, and are mostly studied to understand early internet architecture, and why subnetting is important.

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Subnet Calculator

About subnet calculator.

The subnet calculator lets you enter a subnet range (CIDR) and see IP address information about that range You can type your range directly in CIDR notation , or use the optional Mask pull-down:

  • 74.125.227.0/29
  • 74.125.227.0, then select Optional Mask from dropdown

This is a useful feature for service providers and network operator who frequently allocate and work with subnets. CIDR stands for Classless Inter-Domain Routing, and refers to the standard of dividing the entire IP address space into smaller networks of variable size.

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Subnet Calculator - IP and CIDR

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About the Online Subnet Calculator

Network administrators have been using subnetting for decades to make their networks manageable. Subnets allow you to break large networks into smaller subnets , which are logically separated. If something goes wrong in one part of the network, it does not affect other segments.

The design of IP addressing means every time you add a bit to your subnet mask, you divide the subnet in two parts and assign separate networks. This allows you to build and maintain scalable and efficient networks.

Network Calculator and Free API

This online subnet calculator is the perfect tool to help you figure out out what a network address will be or calculate subnets with masks. This online calculator helps you determine whether a network has enough hosts. also provides an easy way of translating between CIDR notation and dotted-decimal format if needed.

Enter your subnet to get the subnet mask, wildcard mask, network/broadcast address, and number of assignable hosts. You can edit the results and save them on an IP address table and print them for reference.

Use the free subnet API to calculate subnets from a terminal or integrate with software. Save a subnet to your NetworkCalc account to manage IP address assignments.

We designed these tools for systems administrators, network engineers, IT specialists, and students. We hope you find them valuable!

IP Subnet Calculator

What is a subnet, what is a subnet mask, cidr notation, how to calculate network and ip properties, how to use the ip subnet calculator, example of calculating network and ip properties.

This IP subnet calculator displays comprehensive information about IPv4 networks (e.g., the number of usable hosts, IP ranges, etc.) and IP addresses (e.g., private or public, class, etc.). It's useful for designing networks, troubleshooting, and helping you pass your CompTIA Network+ exam.

In the following article, you can read more about CIDR notation and find out what a subnet mask is. Are you interested in administrating networks? You might find our chmod calculator useful, as it helps you understand and solve file permissions issues!

In an Internet Protocol (IP) network, part of the IP address represents the network , while the remainder represents the host (or computer on the network). The act of dividing the IP address is called subnetting . Routers use the network part to exchange data between subnets, and the host part to send data to an individual host. You can estimate how long it will take using the bandwidth calculator .

Note, that this IP subnet calculator is applicable to IPv4 networks , though it also shows the IPv4-mapped IPv6 address, and the 6to4 prefix address, used for transitioning to IPv6.

When designing a network, it's good practice to balance the network and host parts of the IP address, so as not to have too many (limits the number of networks you can route to) or too few hosts (limits the number of computers on the network). A subnet mask is used to create a subnet by allocating several bits in the 32-bit IP address to represent the network. The remaining bits of the IP address represent the host address.

The following table shows an example of an IP address ( 192.0.2.130 ) being subnetted into a network address ( 192.0.2.128 ) and a host address ( 0.0.0.2 ), using a subnet mask of 255.255.255.192 . The calculation requires converting the quad-dotted decimal notation to binary form. A logical AND operation is performed between the IP address and the subnet mask to get the network prefix. You find the host part by flipping the bits of the subnet mask and performing the logical AND operation again with the IP address.

You may find the binary calculator useful if you're unfamiliar with binary operations or need a refresher.

In the early days of the Internet, there were three different main subnet masks , using multiples of 8 bits of ones in the mask. They were named Class A , Class B , and Class C networks, as we show in this table:

The problem with this scheme is that the choice of the number of hosts per network is rather coarse, with large jumps in the number of hosts per network. The solution is Classless Inter-Domain Routing (CIDR) , which eliminates the class model, and lets the network designer assign any number of bits to the network prefix, opening up a more extensive choice of the number of hosts per network.

The notation to indicate the number of bits in the network prefix is a forward-slash , followed by the number of bits . So, a Class A network would be written as /8 , as it uses the first 8 bits in the network mask. This table shows the CIDR notation and the number of usable hosts per subnet:

Rather than looking up network properties in a table, use this IP address subnet calculator as a CIDR calculator to display the associated network properties.

This IP subnet calculator shows you a multitude of network and IP address properties. Let's go through each one to briefly explain how to manually calculate them, linking to further resources for further information.

IP type – public or private?

There are two main types of IP address, public and private . Servers on the public Internet use public addresses, while local networks of computers (e.g., your home network) use private addresses. The following IP address ranges are private addresses :

  • 10.0.0.0 – 10.255.255.255
  • 172.16.0.0 – 172.31.255.255
  • 192.168.0.0 – 192.168.255.255

As well as the network class, IP addresses also historically belonged to classes. The range of IP addresses belonging to each class is defined as :

  • Class A: 0.0.0.0 - 127.255.255.255
  • Class B: 128.0.0.0 - 191.255.255.255
  • Class C: 192.0.0.0 - 223.255.255.255
  • Class D: 224.0.0.0 - 239.255.255.255
  • Class E: 240.0.0.0 - 255.255.255.255

Class D addresses are reserved for multicast traffic (one host sending the same data to many receiving hosts). Class E is reserved, meaning those addresses will not work on the public Internet.

Network address

The network IP address is the first address of the subnet . You calculate it by converting the IP address and subnet mask to binary and performing a bitwise AND logical operation. A router uses this address to forward traffic to the correct network. It isn't possible to assign the network address to a host.

🙋 If you're curious how switching between number systems works, visit our binary converter !

Broadcast address

A host can use the broadcast address to send data to all the other hosts on the subnet. It's the last address on the subnet. We can calculate it by using the network address and adding the total number of addresses (minus one) in the subnet.

First and last host addresses

The next address after the network address is the first address available to be assigned to a host. The address just before the broadcast address is the last address that you can allocate to a host.

Wildcard mask

The wildcard mask is the subnet mask with the bits inverted, therefore selecting the host part of the IP address.

Total number of addresses

We can calculate the total number of addresses in a subnet from the CIDR using the following formula:

Usable number of hosts

The network and broadcast addresses are not available to be assigned to hosts on the network. So, the number of available addresses that you can assign to hosts is the total number of addresses minus two.

Binary subnet mask and IP address

These outputs are the subnet mask and IP address converted to binary format. These are helpful when manually subnetting networks.

This result is the IP address in quad-dotted notation, followed by a forward-slash and the CIDR number.

IP address in integer and hexadecimal form

An IP address is just a number, so you can represent it as an integer (base 10), hexadecimal (base 16), or any other base you like.

in-addr.arpa

This property is a special domain name , used for reverse DNS (Domain Name System) lookups (going from an IP address to a domain name ). The IP address (in quad-dotted format) is reversed and prepended to the domain in-addr.arpa . For example, for the IP address 8.8.4.4 , the PTR (pointer) record for the domain name 4.4.8.8.in-addr.arpa would be looked up and found to point to dns.google .

IPv4-mapped IPv6 address

The Internet is currently upgrading IP addresses from version 4 (represented by 32 bits ) to version 6 (represented by 128 bits ). To help with this transition, hybrid dual-stack IPv6/IPv4 implementations use a 96-bit prefix of 80 bits of zeros and 16 bits of ones , followed by the 32 bit IP address. For example, the IPv4 address 169.291.13.133 maps to an IPv6 address of ::ffff:a9db:0d85 (converting the IP address to hexadecimal). It's also common to use the usual IPv4 quad-dotted decimal notation in the mapped address, like this: ::ffff:169.219.13.133 .

6to4 prefix

Another IPv4 to IPv6 transition strategy is called 6to4 and allows IPv6 data to travel over IPv4 networks . A 6to4 IPv6 address always starts with 2002 and then is followed by the IPv4 address, split into two 16-bit parts, written in hexadecimal, making for a 48-bit long prefix. For example, the 6to4 prefix for the IPv4 address 192.0.2.4 is 2002:c000:0204::/48 . There is then room for an IPv6 16-bit subnet field and 64 bits for hosts.

This subnet calculator is straightforward to use. First select the subnet mask you are interested in exploring. You can reduce the list of subnet masks to choose from by setting the network class option.

Next, enter the IP address , one octet at a time, in the four rows. You will then see all of the network and IP address properties .

Taking an example IP address of 192.168.86.42 , and a subnet mask of 255.255.255.0 (a /24 subnet), let's manually calculate the network and IP properties for this IP address.

Check if the IP address is within any of the ranges of private IP addresses . If it is, then it is a private address. Otherwise, it is a public address. Looking at the ranges, we see that 192.168.86.42 is in the range 192.168.0.0 – 192.168.255.255 - a private address.

Looking through the ranges of each class in the previous section, we see that the IP address 192.168.86.42 is in the range 192.0.0.0 - 223.255.255.255 , so it is a Class C IP address.

Let's go through the calculation of the network address, step-by-step.

Convert both the IP address and subnet mask to binary , and write them down, one above the other. 11000000101010000101011000101010 11111111111111111111111100000000

Perform a bitwise logical AND operation by reading down a column at a time. If there are two ones , write a one as the result. Otherwise, write a zero . 11000000101010000101011000000000

Divide up the binary number into 8-bit blocks and convert it back to decimal . 11000000.10101000.01010110.00000000 192.168.86.0

So, 192.168.86.0 is the network address .

Next, we'll calculate the total number of addresses, as we need that to work out the broadcast address. Use the equation for the total number of addresses, given that the CIDR is 24.

  • 2 ( 32 − CIDR ) 2^{(32 - \text{CIDR})} 2 ( 32 − CIDR )
  • 2 ( 32 − 24 ) 2^{(32 - 24)} 2 ( 32 − 24 )
  • 2 8 2^8 2 8
  • 256 256 256

So, the total number of addresses is 256 .

Now, we can calculate the broadcast address. Convert the network address from binary to decimal, which gives 3,232,257,536 . Add 256 - 1 to get 3,232,257,791 . Then convert this back to binary, separate it into 8-bit blocks, and convert to decimal .

3,232,257,791 11000000101010000101011011111111 11000000.10101000.01010110.11111111 192.168.86.255

So, the broadcast address for our example is 192.168.86.255 .

For the first usable host address, we add one to the network address . While you can do all of the converting to a decimal number, adding one, and switching back to the quad-dotted decimal format, usually, it's easy to work directly with the quad-dotted decimal. Adding one to the network address 192.168.86.0 is simply a matter of adding one to the last octet. Therefore it's 192.168.86.1 for the first usable host address.

The same can be said when calculating the last usable host address, which is the broadcast address minus one . That gives a result of 192.168.86.254 .

To calculate the wildcard mask, convert the subnet mask to binary and flip all the bits . Then switch back to the quad-dotted decimal format.

  • 11111111111111111111111100000000 – binary subnet mask
  • 00000000000000000000000011111111 – bits are flipped
  • 0.0.0.255 – convert back to quad-dotted decimal format

The wildcard mask for our example is 0.0.0.255 .

IP address in integer and hexadecimal

Using the binary form of the IP address, we can convert the binary number to integer (base 10) and hexadecimal (base 16) .

  • 11000000101010000101011000101010 – example IP address as a binary number
  • 3232257578 – integer number
  • 0xc0a8562a – hexadecimal number

Reverse the example IP address 192.168.86.42 to get 42.86.168.192 and put it in front of in-addr.arpa to get 42.86.168.192.in-addr.arpa .

IPv4-mapped IPv6 addresses consist of the prefix ::ffff: followed by the IPv4 address, either displayed in hexadecimal (IPv6 native) format or the IPv4 quad-dotted decimal format. The results for our example IP address is:

  • ::ffff:c0a8:562a
  • ::ffff:192.168.86.42

The 6to4 prefix consists of 2002: followed by the IP address in hexadecimal format. You can convert each octet to hexadecimal individually and write them out in the IPv6 form.

  • 192.168.86.42 is c0.a8.56.2a in hexadecimal
  • 2002:c0a8:562a::/48 is the 6to4 prefix

That's a lot of work here, isn't it? Thanks to our IP address subnet calculator, you can obtain all of this information in a minute!

How do I calculate IP range from subnet mask?

To calculate the starting address of the subnet:

  • Perform a binary AND operation between the IP address and the subnet mask.

Then to calculate the last address in the subnet range:

  • Bitwise, invert the subnet mask.
  • Do a binary OR operation with the first IP address in the subnet.

How do I calculate the broadcast address of a subnet?

The broadcast address is the last IP address within a subnet . You can calculate it by taking the network address (the 1st address within the subnet), adding the number of addresses in the subnet, and then subtracting one.

How do I calculate the total number of addresses in a subnet?

Using the Classless Inter-Domain Routing (CIDR) number of the subnet:

  • Raise two to the power of 32 minus the CIDR number.
  • For example, a /24 subnet has 2³²⁻²⁴ or 256 addresses in total (minus two for the total number of usable IP addresses).

How do I calculate an IPv4 mapped IPv6 address?

To calculate the IPv6 version of an IPv4 address:

  • Set the first 80 bits of the IPv6 address to zero.
  • Set the next 16 bits to 1.
  • Add the 32 bits of the IPv4 address converted to hexadecimal format.
  • For example, 169.291.13.133 maps to an IPv6 address of ::ffff:a9db:0d85 .

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How-To Geek

How do ip addresses work.

Every device connected to a network---computer, tablet, camera, whatever---needs a unique identifier so that other devices know how to reach it.

Quick Links

What is an ip address, what's the difference between ipv4 and ipv6, how does a device get its ip address.

Every device connected to a network---computer, tablet, camera, whatever---needs a unique identifier so that other devices know how to reach it. In the world of TCP/IP networking, that identifier is the Internet Protocol (IP) address.

If you've worked with computers for any amount of time, you've likely been exposed to IP addresses---those numerical sequences that look something like 192.168.0.15. Most of the time, we don't have to deal with them directly, since our devices and networks take care of that stuff behind the scenes. When we do have to deal with them, we often just follow instructions about what numbers to put where. But, if you've ever wanted to dive a little deeper into what those numbers mean, this article is for you.

Related: 8 Common Network Utilities Explained

Why should you care? Well, understanding how IP addresses work is vital if you ever want to troubleshoot why your network isn't working right , or why a particular device isn't connecting the way you'd expect it to. And, if you ever need to set up something a little more advanced---like hosting a game server or media server to which friends from the internet can connect---you'll need to know something about IP addressing. Plus, it's kind of fascinating.

Note: We're going to be covering the basics of IP addressing in this article, the kind of stuff that people who use IP addresses, but never really thought much about them, might want to know. We're not going to be covering some of the more advanced, or professional, level stuff, like IP classes, classless routing, and custom subnetting...but we will point to some sources for further reading as we go along.

An IP address uniquely identifies a device on a network. You've seen these addresses before; they look something like 192.168.1.34.

An IP address is always a set of four numbers like that. Each number can range from 0 to 255. So, the full IP addressing range goes from 0.0.0.0 to 255.255.255.255.

The reason each number can only reach up to 255 is that each of the numbers is really an eight digit binary number (sometimes called an octet). In an octet, the number zero would be 00000000, while the number 255 would be 11111111, the maximum number the octet can reach. That IP address we mentioned before (192.168.1.34) in binary would look like this: 11000000.10101000.00000001.00100010.

assignable ip address range

Computers work with the binary format, but we humans find it much easier to work with the decimal format. Still, knowing that the addresses are actually binary numbers will help us understand why some things surrounding IP addresses work the way they do.

Don't worry, though! We're not going to be throwing a lot of binary or math at you in this article, so just bear with us a bit longer.

The Two Parts of An IP Address

assignable ip address range

A device's IP address actually consists of two separate parts:

  • Network ID: The network ID is a part of the IP address starting from the left that identifies the specific network on which the device is located. On a typical home network, where a device has the IP address 192.168.1.34, the 192.168.1 part of the address will be the network ID. It's custom to fill in the missing final part with a zero, so we might say that the network ID of the device is 192.168.1.0.
  • Host ID: The host ID is the part of the IP address not taken up by the network ID. It identifies a specific device (in the TCP/IP world, we call devices "hosts") on that network. Continuing our example of the IP address 192.168.1.34, the host ID would be 34---the host's unique ID on the 192.168.1.0 network.

On your home network, then, you might see several devices with IP address like 192.168.1.1, 192.168.1.2, 192.168.1 30, and 192.168.1.34. All of these are unique devices (with host IDs 1, 2, 30, and 34 in this case) on the same network (with the network ID 192.168.1.0).

see-who's-connected-to-router

To picture all this a little better, let's turn to an analogy. It's pretty similar to how street addresses work within a city. Take an address like 2013 Paradise Street. The street name is like the network ID, and the house number is like the host ID. Within a city, no two streets will be named the same, just like no two network IDs on the same network will be named the same. On a particular street, every house number is unique, just like all host iDs within a particular network ID are unique.

The Subnet Mask

So, how does your device determine which part of the IP address is the network ID and which part the host ID? For that, they use a second number that you'll always see in association with an IP address. That number is called the subnet mask.

On most simple networks (like the ones in homes or small businesses), you'll see subnet masks like 255.255.255.0, where all four numbers are either 255 or 0. The position of the changes from 255 to 0 indicate the division between the network and host ID. The 255s "mask out" the network ID from the equation.

assignable ip address range

Note: The basic subnet masks we're describing here are known as default subnet masks. Things get more complicated than this on bigger networks. People often use custom subnet masks (where the position of the break between zeros and ones shifts within an octet) to create multiple subnets on the same network. That's a little beyond the scope of this article, but if you're interested, Cisco has a pretty good guide on subnetting .

The Default Gateway Address

Related: Understanding Routers, Switches, and Network Hardware

In addition to the IP address itself and the associated subnet mask, you'll also see a default gateway address listed along with IP addressing information. Depending on the platform you're using, this address might be called something different. It's sometimes called the "router," "router address," default route," or just "gateway." These are all the same thing. It's the default IP address to which a device sends network data when that data is intended to go to a different network (one with a different network ID) than the one the device is on.

The simplest example of this is found in a typical home network.

If you have a home network with multiple devices, you likely have a router that's connected to the internet through a modem. That router might be a separate device, or it might be part of a modem/router combo unit supplied by your internet provider. The router sits between the computers and devices on your network and the more public-facing devices on the internet, passing (or routing) traffic back and forth.

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Say you fire up your browser and head to www.howtogeek.com. Your computer sends a request to our site's IP address. Since our servers are on the internet rather than on your home network, that traffic is sent from your  PC to your router (the gateway), and your router forwards the request on to our server. The server sends the right information back to your router, which then routes the information back to the device that requested it, and you see our site pop up in your browser.

Typically, routers are configured by default to have their private IP address (their address on the local network) as the first host ID. So, for example, on a home network that uses 192.168.1.0 for a network ID, the router is usually going to be 192.168.1.1. Of course, like most things, you can configure that to be something different if you want.

Related: How to Find Your Router's IP Address on Any Computer, Smartphone, or Tablet

DNS Servers

There's one final piece of information you'll see assigned alongside a device's IP address, subnet mask, and default gateway address: the addresses of one or two default Domain Name System (DNS) servers. We humans work much better with names than numerical addresses. Typing www.howtogeek.com into your browser's address bar is much easier than remembering and typing our site's IP address.

DNS works kind of like a phone book, looking up human-readable things like website names, and converting those to IP addresses. DNS does this by storing all that information on a system of linked DNS servers across the internet. Your devices need to know the addresses of DNS servers to which to send their queries.

Related: What Is DNS, and Should I Use Another DNS Server?

On a typical small or home network, the DNS server IP addresses are often the same as the default gateway address. Devices send their DNS queries to your router, which then forwards the requests on to whatever DNS servers the router is configured to use. By default, these are usually whatever DNS servers your ISP provides, but you can change those to use different DNS servers if you want. Sometimes, you might have better success using DNS servers provided by third parties , like Google or OpenDNS.

assignable ip address range

You also may have noticed while browsing through settings a different type of IP address, called an IPv6 address. The types of IP addresses we've talked about so far are addresses used by IP version 4 (IPv4)---a protocol developed in the late 70s. They use the 32 binary bits we talked about (in four octets) to provide a total of 4.29 billion possible unique addresses. While that sounds like a lot, all the publicly available addresses were long ago assigned to businesses. Many of them are unused, but they are assigned and unavailable for general use.

In the mid-90s, worried about the potential shortage of IP addresses, the internet Engineering Task Force (IETF) designed IPv6. IPv6 uses a 128-bit address instead of the 32-bit address of IPv4, so the total number of unique addresses is measured in the undecillions---a number big enough that it's unlikely to ever run out.

Unlike the dotted decimal notation used in IPv4, IPv6 addresses are expressed as eight number groups, divided by colons. Each group has four hexadecimal digits that represents 16 binary digits (so, it's referred to as a hextet). A typical IPv6 address might look something like this:

2601:7c1:100:ef69:b5ed:ed57:dbc0:2c1e

The thing is, the shortage of IPv4 addresses that caused all the concern ended up being mitigated to a large extent by the increased use of private IP addresses behind routers. More and more people created their own private networks, using those private IP addresses that aren't exposed publicly.

So, even though IPv6 is still a major player and that transition will still happen, it never happened as fully as predicted---at least not yet. If you're interested in learning more, check out this history and timeline of IPv6 .

assignable ip address range

Now that you know the basics of how IP addresses work, let's talk about how devices get their IP addresses in the first place. There are really two types of IP assignments: dynamic and static.

Related: How to Find Any Device's IP Address, MAC Address, and Other Network Connection Details

A dynamic IP address is assigned automatically when a device connects to a network. The vast majority of networks today (including your home network) use something called Dynamic Host Configuration Protocol (DHCP) to make this happen. DHCP is built into your router. When a device connects to the network, it sends out a broadcast message requesting an IP address. DHCP intercepts this message, and then assigns an IP address to that device from a pool of available IP addresses.

There are certain private IP address ranges  routers will use for this purpose. Which is used depends on who made your router, or how you have set things up yourself. Those private IP ranges include:

  • 10.0.0.0 - 10.255.255.255: If you're a Comcast/Xfinity customer, the router provided by your ISP assigns addresses in this range. Some other ISPs also use these addresses on their routers, as does Apple on their AirPort routers.
  • 192.168.0.0 - 192.168.255.255: Most commercial routers are set up to assign IP addresses in this range. For example, most Linksys routers use the 192.168.1.0 network, while D-Link and Netgear both use the 198.168.0.0 range
  • 172.16.0.0 - 172.16.255.255: This range is rarely used by any commercial vendors by default.
  • 169.254.0.0 - 169.254.255.255: This is a special range used by a protocol named Automatic Private IP Addressing. If your computer (or other device) is set up to retrieve its IP address automatically, but cannot find a DHCP server, it assigns itself an address in this range. If you see one of these addresses, it tells you that your device could not reach the DHCP server when it came time to get an IP address, and you may have a networking issue or trouble with your router.

The thing about dynamic addresses is that they can sometimes change. DHCP servers lease IP addresses to devices, and when those leases are up, the devices must renew the lease. Sometimes, devices will get a different IP address from the pool of addresses the server can assign.

Most of the time, this is not a big deal, and everything will "just work". Occasionally, however, you might want to give a device an IP address that does not change. For example, maybe you have a device that you need to access manually, and you find it easier to remember an IP address than a name. Or maybe you have certain apps that can only connect to network devices using their IP address.

In those cases, you can assign a static IP address to those devices. There are a couple of ways to do this. You can  manually configure the device with a static IP address yourself, although this can sometimes be janky. The other, more elegant solution is to configure your router to assign static IP addresses to certain devices during what would normally be dynamic assignment by the DHCP server. That way, the IP address never changes, but you don't interrupt the DHCP process that keeps everything working smoothly.

Notes : Networks, Subnets, and CIDR

There are networks known as classful and classless. The first plan adopted and used widely by the Internet community were classful networks. So named because three address classes: A, B, and C were defined with assignable IP address space. These classes, however, disproportionately distributed the number of available IP addresses. A new method to identify networks and allocate IP addresses was needed to support the continued growth of the Internet. The new method is named classless because it does away with the idea of classes altogether. It is commonly known as Classless Inter-Domain Routing (CIDR). It is much more flexible than classful networks and is what the Internet uses today. Classful networks are still used by many devices, so it is important to understand both classful and classless networking.

IPv4 Overview

An IPv4 address contains 32-bits. It is usually represented in dotted decimal quad notation so it is easier to read and communicate. Computers, of course, read this information in binary form. And in order to calculate subnet masks, network addresses, and broadcast addresses, the binary value must be known.

Converting a dotted decimal IP address to binary is simple. Given that there are 4 numbers, each decimal number is represented in binary as an octet. The high order bits in binary are always the leftmost ones.

The largest single value an IP address may have in decimal is 255 since this is the sum when all of the bits are added together, i.e. 2 7 + 2 6 + 2 5 + 2 4 + 2 3 + 2 2 + 2 1 + 2 0 . When all of the bits are turned off, the number is 0. The range of an IP address is therefore 0 - 255, 256 values.

The following is how the IP address 68.125.16.250 would be converted and represented in binary form.

The end result looks like 01000100011111010001000011111010.

Classful Networks

Once an IP address is represented in binary format, the class of network can be determined rather easily. Beginning from the left of the IP address, the first bit that is not a "1" indicates whether it is a Class A, Class B, Class C, Class D, or Class E network.

For class A networks, the high order (leftmost) bit is always a "0". For class B networks, the high order bits are always a "1" followed by a "0". For class C networks, the high order bits are always a "1" followed by a "1" followed by a "0".

Not all of the address ranges in the above table are assignable. The IANA has reserved several address spaces for special or private use. Some of the most well-known reserved address spaces are listed in the table below .

Subnet Masks

Subnet masks represent what part of an IP address is used to determine network information versus host information. For a class B network, the subnet mask uses 16 bits, allowing the remaining 16 bits to be used for host information.

The total number of available hosts on a network can be determined from it's subnet mask. Since a class B network uses 16 bits for its subnet mask, it leaves 16 bits available for host information. 2 16 = 65,536. All hosts need a network address and a broadcast address. The network and broadcast addresses are indicated by either all 1s or all 0s in the host information part of an IP address. With those two addresses always reserved, the total number of assignable hosts for a class B network is 2 16 - 2 = 65,534.

The total number of networks a class address may have is calculated by subtracting the number of bits in the subnet mask from the number of bits used to determine which class of network it is. For example, a class A network has an 8-bit subnet mask. Only 1 bit is used to determine that it is a class A network. Subtract 8 from 1 and that leaves 7 bits available for networks. 2 7 is 128. So, there is only room for 128 class A networks.

Classless Networks

Forget class A, B, and C now. Classless networks don't use it at all, hence the name. Instead, CIDR networks are identified with a trailing "/" slash and a number that indicates how many bits are used to identify the network portion of the address. Like a class C address in classful networking, a /24 would indicate that 24-bits are used to identify the network and the remaining 8-bits are used to identify the host. Unlike classful networking, CIDR provides much more flexibility than 8, 16, and 24-bit network masks. Under CIDR, the number of bits used to indicate the network portion of the address can be from /8 to /30 although more commonly only /13 to /29 are used. This gives network administrators the flexibility to assign addresses from 6 - 524,286 to match the needs of an organization.

CIDR Available Hosts

The formula to calculate the number of assignable IP address to CIDR networks is similar to classful networking. Subtract the number of network bits from 32. Raise 2 to that power and subtract 2 for the network and broadcast addresses. For example, a /24 network has 2 32-24 - 2 addresses available for host assignment.

As the table indicates, two /29 networks equals a /28 network. Two /28 networks equals a /27 network. Two /27 networks equals a /26 network. And so on, and so on. The notion of combining two smaller networks into a larger one is another benefit of classless networks named supernetting . In order to create a supernet the smaller networks must be contiguous. For example, 192.0.2.240/29 and 192.0.2.248/29 can form a supernet 192.0.2.240/28, but 192.0.2.240/29 and 192.0.2.8/29 could not.

CIDR Available Networks (subnetting)

How many /29 networks can fit into a /24 network? Or how many /21 networks can fit into a /17 network? The best way to explain the formula is to show it. The following illustrates how many /21 networks can fit into a /17 network.

  • Subtract the network bits from 32. /17 = 32-17 and /21 = 32-21
  • Raise 2 to that power. 2 32-17 and 2 32-21
  • Divide the larger network by the smaller one. 2 32-17 / 2 32-21 = 2 15 / 2 11 = 2 15-11 = 2 4 = 16

As the example shows, a /17 network could be divided into sixteen /21 networks. Spot the shortcut in the steps? How many /29 networks in a /24?

2 8-3 = 2 5 = 32

CIDR Networks

Since CIDR address spaces can overlap byte boundaries, the method to tell which address is a part of which network is a little trickier than with classful networking. Everything that needs to be known is indicated by the "/" number, however. Given a network address 172.16.0.0/21, it is known that the first 21 bits of that address represent the network portion. That leaves 11 bits for host information, about 2,000 host addresses. To easier see what that range looks like, convert 172.16.0.0 into binary. In binary, the number looks like 10101100.00010000.00000 000.00000000. The bold numbers show the /21 network mask. No modification can be done to network portion of the address. The remaining 11 bits are available for host assignment on the network. After the bold section, the remaining 3 bits in the third octet can be added up for a maximum value of decimal 7 (2 2 + 2 1 + 2 0 ). All of the bits in the last octet are available and when converted to decimal equal 255. With all of the bits turned on (all 1s), the decimal number turns out to be 172.16.7.255. This is the end range of the 172.16/21 network, 172.16.0.0 - 172.16.7.255.

CIDR Subnet Mask

The process to determine the subnet mask for a CIDR address is straight forward. The number of bits in the network portion of the address are converted to 1s and right padded with 0s until there are 32 numbers. The sequence of numbers is then divided into 4 octets. From then, it is a matter of converting the 4 octets from binary to decimal.

Reserved IPv4 Address Spaces

The IANA is "dedicated to preserving the central coordinating functions of the global Internet for the public good." Among their other tasks, they coordinate and allocate IP address space.

This table represents the most common reserved or special use address spaces for IPv4. A full list of IPv4 classifications can be found on the IANA website.

CIDR Calculator

Networkcalculator.ca.

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Fill in the IP address in CIDR notation. The calculator will display the network address, usable IPs, broadcast address, and network mask.

  • All IP address parts must contain an integer not greater than 255
  • The CIDR prefix must be an integer greater than 0 and not greater than 30 1
  • Blank IP field = 0
  • Leading and trailing dots in fields are removed

If you enter a start IP and prefix that is not on the CIDR boundary for the specified prefix, the calculator will auto-convert to display the range that is on the proper CIDR boundary for the specific prefix and contains the start IP address.

The smallest possible subnet is 4 IPs: a network number, 2 usable IPs, and a broadcast address. 1 Thus the CIDR prefix may not be greater than 30.

Private IPv4 addresses as per RFC 1918

Automatic Private IP addresses reserved by IANA.

What Is An IP Range

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Introduction

As the internet continues to evolve and expand, understanding the concept of an IP range becomes increasingly important. Whether you’re a website owner, network administrator, or simply a curious internet user, knowing what an IP range is and how it works can provide valuable insights into the world of networking and connectivity.

An IP range, short for Internet Protocol range, refers to a range of IP addresses that are grouped together based on a specific pattern. It allows for the identification and communication of devices within a certain network. Each device connected to the internet is assigned a unique IP address, which serves as its “digital signature.” These IP addresses can be classified and grouped in various ways to form IP ranges.

The benefits of using IP ranges are manifold. They enable efficient and organized management of network devices, making it easier to control access, monitor traffic, and apply security measures. By defining IP ranges, administrators can regulate which devices or users are allowed or denied access to specific resources or services.

Defining an IP range involves specifying the starting and ending IP addresses that fall within a particular range. For example, an IP range could encompass all IP addresses between 192.168.0.1 and 192.168.0.255. This allows for the grouping and management of devices within that range.

There are two main types of IP ranges: classful and classless. Classful IP ranges follow a predefined structure, meaning the network identification and host identification portions of the IP address are fixed. Classless IP ranges, on the other hand, are more flexible and allow for a wider range of IP addresses within a given network.

What is an IP Range?

An IP range, also known as an Internet Protocol range, is a set of consecutive IP addresses that are grouped together based on specific criteria. In simple terms, it is a range of numbers that represents a block of IP addresses. Each IP address consists of a series of four numbers separated by periods, such as 192.168.0.1. The range typically includes a starting IP address and an ending IP address.

IP ranges are used to define and manage networks, allowing devices within the range to communicate with each other and access network resources. They play a crucial role in routing data packets across the internet and ensure that information reaches its intended destination.

By using IP ranges, network administrators can efficiently organize and control access to their networks. For example, a company might assign a specific IP range to its employees for internal use. This allows for easy identification of company devices and allows network administrators to implement security measures and monitor network activity.

Additionally, IP ranges are also vital for managing and allocating IP addresses within an organization or internet service provider (ISP). ISPs typically have a pool of IP addresses that they divide into smaller ranges to assign to their customers. This ensures that multiple users can connect to the internet with unique IP addresses without overlap.

IP ranges can be further classified into two main types: classful and classless. Classful IP ranges were used in the early days of the internet and followed a strict hierarchical structure. However, with the increase in the number of devices connected to the internet, classless IP ranges have become more common. Classless Inter-Domain Routing (CIDR) notation allows for more flexibility in defining IP ranges and efficiently allocating IP addresses.

Benefits of using IP Ranges

Using IP ranges offers numerous benefits for network administrators and organizations. By organizing and managing devices within specific IP ranges, the following advantages can be realized:

  • Efficient Network Management: IP ranges provide a systematic approach to managing devices within a network. By assigning devices to specific ranges, administrators can easily identify and categorize devices based on their purpose, location, or user group. This simplifies network administration tasks such as monitoring, troubleshooting, and security configuration.
  • Enhanced Security: IP ranges enable administrators to implement granular security measures. By assigning different access permissions to different IP ranges, administrators can control which devices or users have access to specific network resources. This helps protect sensitive data and restrict unauthorized access to critical systems.
  • Streamlined Traffic Monitoring: By defining IP ranges, administrators can monitor network traffic more effectively. They can analyze network activity within specific ranges to identify potential issues, troubleshoot problems, and optimize network performance. This allows for better resource allocation and improved overall network efficiency.
  • Improved Resource Allocation: With IP ranges, administrators can allocate network resources more efficiently. By grouping devices into specific ranges, they can better distribute network resources such as bandwidth, IP addresses, and DHCP configurations. This ensures fair and optimized usage of network resources for all devices.

Furthermore, IP ranges are particularly useful in large organizations or multi-site networks. They enable administrators to segment the network into smaller, manageable units, improving overall network performance and simplifying troubleshooting. In addition, IP ranges ease the process of adding or removing devices from the network by providing a structured framework for device management and IP address assignment.

Overall, utilizing IP ranges empowers network administrators to exert greater control and flexibility over their networks. It enhances network security, allows for efficient resource allocation, and streamlines network management processes. By leveraging IP ranges effectively, organizations can optimize their network infrastructure for enhanced performance and productivity.

How to Define an IP Range

Defining an IP range involves determining the starting and ending IP addresses that fall within a specific range. This process allows network administrators to group devices and allocate resources efficiently. Here are the steps to define an IP range:

  • Identify the Purpose: Determine the purpose or criteria for creating the IP range. For example, you might want to create a range for devices in a specific department or for a particular location.
  • Plan the IP Range: Decide on the range of IP addresses that will be included in the defined range. Consider factors such as the number of devices, the potential growth of the network, and any specific requirements for subnetting or VLANs.
  • Choose a Notation: Decide on the notation you will use to represent the IP range. The most common notation is CIDR (Classless Inter-Domain Routing), where the range is represented as a subnet mask followed by the network address. For example, 192.168.0.0/24 represents an IP range from 192.168.0.1 to 192.168.0.254.
  • Calculate the Subnet Mask: If using CIDR notation, calculate the corresponding subnet mask for the desired range. The subnet mask determines the number of host bits in the IP address and the size of the network. For example, /24 corresponds to a subnet mask of 255.255.255.0.
  • Assign IP Addresses: Once you have determined the starting and ending IP addresses, assign them to the devices within the range. This can be done manually or through DHCP (Dynamic Host Configuration Protocol) for automatic assignment.
  • Configure Network Devices: Update the network devices, such as routers, switches, and firewalls, to recognize and route traffic to the newly defined IP range. This step ensures that devices within the range can communicate with each other and access network resources.

It is essential to document the defined IP ranges and keep track of any changes or additions. This documentation will aid in network troubleshooting, planning for future expansion, and ensuring a consistent and organized network infrastructure.

By following these steps, network administrators can effectively define and implement IP ranges tailored to their specific requirements. This allows for efficient device management, resource allocation, and network optimization.

Classful vs Classless IP Ranges

When it comes to IP ranges, there are two main types: classful and classless. Understanding the differences between these two types is crucial for network administrators and anyone working with IP addresses. Let’s explore the distinctions between classful and classless IP ranges:

Classful IP Ranges: Classful IP addressing was the original method used to allocate IP addresses. In classful addressing, IP addresses are divided into three classes: Class A, Class B, and Class C.

  • Class A: Class A addresses have a range from 1.0.0.0 to 126.0.0.0 and support a large number of networks with a large number of hosts.
  • Class B: Class B addresses range from 128.0.0.0 to 191.255.0.0 and provide a medium-sized network with a moderate number of hosts.
  • Class C: Class C addresses span from 192.0.0.0 to 223.255.255.0 and accommodate small networks with a limited number of hosts.

The main limitation of classful IP addressing is that it allocates a fixed number of host bits within each class, regardless of the actual number of devices in the network. This often leads to inefficient utilization of IP addresses, as many addresses within each class may remain unused.

Classless IP Ranges: To address the limitations of classful addressing, classless IP addressing was introduced. Classless Inter-Domain Routing (CIDR) notation is used to represent classless IP ranges.

CIDR notation provides more flexibility in allocating IP addresses by allowing for the variable length of the network prefix. It follows the format of IP address followed by a slash (/) and the number of bits in the network prefix. For example, 192.168.0.0/24 represents a classless IP range with a network prefix of 24 bits.

This flexibility allows for more efficient utilization of IP addresses. Instead of being limited to fixed class-based ranges, classless IP ranges can be subdivided further into smaller subnets as per the organization’s requirements. This results in better allocation of IP addresses and reduces the wastage of unused addresses.

Classless IP ranges also have the advantage of allowing for variable-sized networks, accommodating both small and large networks with the appropriate number of hosts. It provides greater scalability and supports hierarchical routing, making network management and troubleshooting more efficient.

In summary, classful IP addressing uses fixed classes for address allocation, while classless IP addressing offers more flexibility and efficient utilization of IP addresses through CIDR notation. Classless IP ranges provide scalability, hierarchical routing, and support for networks of various sizes.

Understanding CIDR Notation

Classless Inter-Domain Routing (CIDR) notation is a method used to represent IP addresses and IP ranges in a more flexible and efficient manner. CIDR notation is widely used in classless IP addressing, allowing for more granular allocation of IP addresses. Let’s delve into the key aspects of CIDR notation:

CIDR notation consists of an IP address followed by a forward slash (/) and a number, which represents the network prefix length. The network prefix length denotes the number of bits in the network portion of the IP address.

For example, an IP address of 192.168.0.0/24 indicates that the first 24 bits of the IP address form the network portion, while the remaining bits represent the host portion. This means that there are 24 bits reserved for network identification and 8 bits available for devices within the network.

CIDR notation simplifies the representation of IP ranges. For instance, an IP range starting from 192.168.0.0 to 192.168.0.255 can be expressed as 192.168.0.0/24. This notation eliminates the need to list all the individual IP addresses in the range, making it more concise and manageable.

CIDR notation also allows for the creation of subnets within an IP range. By reducing the network prefix length, network administrators can divide the range into smaller subnets. For instance, an IP range of 192.168.0.0/24 can be subnetted into two /25 subnets, each accommodating up to 128 devices.

CIDR notation enables efficient IP address allocation and hierarchical routing. It supports the aggregation of multiple networks into a single, larger network block. This aggregation helps reduce the size of routing tables and improves routing efficiency across networks.

Network administrators and ISPs rely on CIDR notation to allocate IP addresses based on the specific needs of the network. It allows for greater flexibility in assigning IP addresses and accommodating networks of varying sizes.

Understanding and utilizing CIDR notation is essential for managing IP addresses effectively. It provides a standardized and scalable approach to IP addressing, enabling efficient allocation, organization, and routing of IP networks.

How to Calculate the Number of IP Addresses in a Given Range

Calculating the number of IP addresses within a given range is essential for proper IP address management and resource allocation. By determining the size of an IP range, network administrators can effectively plan network capacity and ensure sufficient addresses are available. Here’s how to calculate the number of IP addresses in a given range:

1. Determine the Network Prefix Length: First, identify the network prefix length or subnet mask of the given IP range. The subnet mask specifies the number of network bits in the IP address. For instance, a /24 subnet mask corresponds to 255.255.255.0.

2. Calculate the Number of Host Bits: Subtract the network prefix length from the total number of bits in an IP address. For example, with a /24 subnet mask, there are 8 bits remaining for the host portion (32 – 24 = 8).

3. Determine the Number of Hosts: Calculate the total number of possible host addresses within the host portion. This can be done by raising 2 to the power of the number of host bits. For example, with 8 host bits, there are 2^8, or 256, possible host addresses.

4. Account for Reserved Addresses: Remember that not all host addresses within the range are usable. Some addresses may be reserved for special purposes, such as the network address (first address) and the broadcast address (last address). Subtract these reserved addresses from the total number of possible host addresses to get the number of usable host addresses.

5. Consider Additional Subnetting: If the given IP range is further divided into smaller subnets, you will need to calculate the number of host addresses in each subnet individually. Repeat the steps above for each subnet to determine the number of usable host addresses.

It’s important to note that calculating the number of IP addresses within a given range provides an estimation of potential addresses. In reality, not all addresses may be available for use due to network infrastructure requirements, reserved addresses, or address allocation policies.

By accurately calculating the number of IP addresses, network administrators can allocate IP resources effectively, plan for future growth, and ensure the availability of sufficient addresses for their network requirements.

Common Uses for IP Ranges

IP ranges serve a variety of purposes in networking and are widely utilized in different contexts. Understanding the common use cases for IP ranges can help network administrators optimize their network infrastructure and enhance overall connectivity. Here are some of the common uses for IP ranges:

  • Network Segmentation: IP ranges are often used to divide a network into smaller segments or subnets. This segmentation helps improve network performance, enhance security, and simplify network management. Each subnet can be allocated its own IP range, allowing for efficient allocation of network resources and isolation of different departments or functions.
  • Device Classification and Access Control: IP ranges enable administrators to classify and control access to network devices based on their IP addresses. Specific IP ranges can be assigned to different groups of devices or users, allowing administrators to apply customized security policies and control network access. This helps protect sensitive resources and restrict unauthorized access.
  • Virtual Private Networks (VPNs): IP ranges play a crucial role in setting up and managing virtual private networks. VPNs use specific IP ranges to establish secure connections between remote networks or devices over the public internet. IP ranges ensure that devices within the VPN are assigned unique and identifiable addresses, facilitating the secure transfer of data.
  • IP Address Assignment: IP ranges are used to allocate IP addresses to individual devices within a network. Dynamic Host Configuration Protocol (DHCP) servers assign IP addresses from designated ranges to devices as they connect to the network. This allows for automated and efficient IP address management, reducing the manual effort required for address assignment.
  • Network Monitoring and Traffic Analysis: By defining IP ranges, network administrators can focus their monitoring and analysis efforts on specific segments of the network. This targeted approach enables better visibility into network traffic, identification of potential bottlenecks or security threats, and more accurate performance analysis. It allows for effective troubleshooting and optimization of network resources.

These are just a few examples of the common uses for IP ranges. The flexibility and versatility of IP ranges make them an essential tool in network administration, enabling efficient resource allocation, enhanced security, and simplified network management.

Limitations of IP Ranges

While IP ranges offer many benefits in network management and resource allocation, they also have some limitations that need to be considered. Understanding these limitations can help network administrators make informed decisions and overcome potential challenges. Here are some key limitations of IP ranges:

  • Static Nature: IP ranges are typically defined at the network configuration stage and remain relatively static. This means that changes to the network structure or addition/removal of devices may require reallocation or adjustment of IP ranges. It can be time-consuming and may disrupt network connectivity.
  • Address Exhaustion: With the increasing number of devices connected to the internet, there is a finite number of IP addresses available. IPv4, the most widely used IP protocol, has a limited number of addressable IP ranges, and address exhaustion is a real concern. This has led to the adoption of IPv6, which expands the available IP address space.
  • Address Wastage: IP ranges allocated to specific networks may not utilize the entire range of addresses assigned to them. This can result in unused IP addresses and wasted resources. Network administrators need to regularly review and manage IP address allocations to ensure efficient utilization.
  • Routing Complexity: As networks grow in size and complexity, routing IP packets becomes a challenging task. When networks are divided into multiple subnets using IP ranges, routing tables need to be carefully configured and monitored to ensure efficient packet delivery across the network. Improper configuration can lead to network congestion and suboptimal performance.
  • Management Overhead: As the number of IP ranges and subnets increases, managing and coordinating network changes can become complex. Adding or removing IP ranges, adjusting subnet allocations, and maintaining accurate IP documentation require effective management practices and close coordination among network administrators.
  • Overlap and Address Conflicts: Improperly defined IP ranges can result in overlapping subnets or IP address conflicts within a network. This can lead to network connectivity issues, routing problems, and difficulty in identifying the source of network outages or performance degradation.

Despite these limitations, IP ranges continue to be a widely used and crucial tool in network administration. Network administrators can mitigate these limitations through effective planning, regular network monitoring, and adopting technologies that prioritize efficient IP address allocation and usage. Additionally, the adoption of newer IP protocols, such as IPv6, helps address the challenges related to address space exhaustion.

Understanding IP ranges is essential for effective network management and resource allocation. IP ranges allow network administrators to organize devices, control access, and optimize connectivity within a network. By grouping devices based on IP addresses, administrators can implement security measures, monitor network traffic, and allocate network resources more efficiently.

There are two main types of IP ranges: classful and classless. Classful IP ranges follow a predefined structure, while classless IP ranges provide greater flexibility in allocating IP addresses. Classless Inter-Domain Routing (CIDR) notation is commonly used to represent IP ranges and allows for more efficient IP address allocation and subnetting.

Calculating the number of IP addresses within a given range helps administrators plan for network expansion, manage IP resources effectively, and ensure adequate address availability. Additionally, understanding the limitations of IP ranges, such as static nature and address exhaustion, helps network administrators devise strategies to overcome challenges and optimize network performance.

IP ranges are commonly used for network segmentation, device classification, VPNs, IP address assignment, and network monitoring. They offer a structured approach to network management, enhance security, and streamline resource allocation. However, administrators must be mindful of the limitations, such as routing complexity and address conflicts, and employ best practices to address these challenges.

In conclusion, IP ranges play a vital role in modern networking. They enable efficient organization, access control, and allocation of network resources. Network administrators who understand how to define IP ranges, calculate addresses, and navigate the limitations associated with IP ranges can optimize their networks for improved connectivity, security, and performance.

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Number Resources

We are responsible for global coordination of the Internet Protocol addressing systems, as well as the Autonomous System Numbers used for routing Internet traffic.

Currently there are two types of Internet Protocol (IP) addresses in active use: IP version 4 (IPv4) and IP version 6 (IPv6). IPv4 was initially deployed on 1 January 1983 and is still the most commonly used version. IPv4 addresses are 32-bit numbers often expressed as 4 octets in “dotted decimal” notation (for example, 192.0.2.53 ). Deployment of the IPv6 protocol began in 1999. IPv6 addresses are 128-bit numbers and are conventionally expressed using hexadecimal strings (for example, 2001:0db8:582:ae33::29 ).

Both IPv4 and IPv6 addresses are generally assigned in a hierarchical manner. Users are assigned IP addresses by Internet service providers (ISPs). ISPs obtain allocations of IP addresses from a local Internet registry (LIR) or National Internet Registry (NIR), or from their appropriate Regional Internet Registry (RIR):

Our primary role for IP addresses is to allocate pools of unallocated addresses to the RIRs according to their needs as described by global policy and to document protocol assignments made by the IETF . When an RIR requires more IP addresses for allocation or assignment within its region, we make an additional allocation to the RIR. We do not make allocations directly to ISPs or end users except in specific circumstances, such as allocations of multicast addresses or other protocol specific needs.

IP Address Allocations

Internet protocol version 4 (ipv4).

  • IPv4 Address Space
  • IPv4 Multicast Address Assignments
  • IPv4 Special Purpose Address Registry
  • IPv4 Recovered Address Space Registry
  • Bootstrap Service Registry for IPv4 Address Space

Internet Protocol Version 6 (IPv6)

  • IPv6 Address Space
  • IPv6 Global Unicast Allocations
  • IPv6 Parameters (Parameters described for IPv6, including header types, action codes, etc.)
  • IPv6 Anycast Address Allocations
  • IPv6 Multicast Address Allocations
  • IPv6 Sub-TLA Assignments (DEPRECATED)
  • IANA IPv6 Special Registry
  • Bootstrap Service Registry for IPv6 Address Space
  • Announcement of Worldwide Deployment of IPv6 (14 July 1999)
  • RIR Comparative Policy Overview

Autonomous System Number Allocations

  • Autonomous System Numbers
  • Special-Purpose AS Number Assignments
  • Bootstrap Service Registry for AS Number Space
  • Internet Number Resource Request Procedure

Regional Internet Registry Creation

  • Criteria for Establishment of New Regional Internet Registries (ICP-2) (4 June 2001)
  • IANA Report on Recognition of LACNIC as a Regional Internet Registry (7 November 2002)
  • IANA Report on Recognition of AfriNIC as a Regional Internet Registry (8 April 2005)

Technical Documentation

  • RFC 4632 — Classless Inter-domain Routing (CIDR): The Internet Address Assignment and Aggregation Plan
  • RFC 1918 — Address Allocation for Private Internets
  • RFC 5737 — IPv4 Address Blocks Reserved for Documentation
  • RFC 4291 — Internet Protocol Version 6 (IPv6) Addressing Architecture
  • RFC 3587 — IPv6 Global Unicast Address Format
  • RFC 6177 — IPv6 Address Assignment to End Sites
  • RFC 6890 — Special-Purpose IP Address Registries
  • RFC 7020 — The Internet Numbers Registry System
  • RFC 7249 — Internet Numbers Registries
  • Locally Served DNS Zones

In the IPv4 IP address space, there are five classes: A, B, C, D and E. Each class has a specific range of IP addresses (and ultimately dictates the number of devices you can have on your network). Primarily, class A, B, and C are used by the majority of devices on the Internet. Class D and class E are for special uses.

The list below shows the five available IP classes, along with the number of networks each can support and the maximum number of hosts (devices) that can be on each of those networks. The four octets that make up an IP address are conventionally represented by a.b.c.d - such as 127.10.20.30.

Additionally, information is also provided on private addresses and loop address (used for network troubleshooting).

Class A Public & Private IP Address Range

Class A addresses are for networks with large number of total hosts. Class A allows for 126 networks by using the first octet for the network ID. The first bit in this octet, is always zero. The remaining seven bits in this octet complete the network ID. The 24 bits in the remaining three octets represent the hosts ID and allows for approximately 17 million hosts per network. Class A network number values begin at 1 and end at 127.

  • First octet value range from 1 to 127
  • Private IP Range: 10.0.0.0 to 10.255.255.255 (See Private IP Addresses below for more information)
  • Subnet Mask: 255.0.0.0 (8 bits)
  • Number of Networks: 126
  • Number of Hosts per Network: 16,777,214

Class B Public & Private IP Address Range

Class B addresses are for medium to large sized networks. Class B allows for 16,384 networks by using the first two octets for the network ID. The first two bits in the first octet are always 1 0. The remaining six bits, together with the second octet, complete the network ID. The 16 bits in the third and fourth octet represent host ID and allows for approximately 65,000 hosts per network. Class B network number values begin at 128 and end at 191.

  • First octet value range from 128 to 191
  • Private IP Range: 172.16.0.0 to 172.31.255.255 (See Private IP Addresses below for more information)
  • Subnet Mask: 255.255.0.0 (16 bits)
  • Number of Networks: 16,382
  • Number of Hosts per Network: 65,534

Class C Public & Private IP Address Range

Class C addresses are used in small local area networks (LANs). Class C allows for approximately 2 million networks by using the first three octets for the network ID. In a class C IP address, the first three bits of the first octet are always 1 1 0. And the remaining 21 bits of first three octets complete the network ID. The last octet (8 bits) represent the host ID and allows for 254 hosts per network. Class C network number values begins at 192 and end at 223.

  • First octet value range from 192 to 223
  • Private IP Range: 192.168.0.0 to 192.168.255.255 (See Private IP Addresses below for more information)
  • Special IP Range: 127.0.0.1 to 127.255.255.255 (See Special IP Addresses below for more information)
  • Subnet Mask: 255.255.255.0 (24 bits)
  • Number of Networks: 2,097,150
  • Number of Hosts per Network: 254

Class D IP Address Range

Class D IP addresses are not allocated to hosts and are used for multicasting. Multicasting allows a single host to send a single stream of data to thousands of hosts across the Internet at the same time. It is often used for audio and video streaming, such as IP-based cable TV networks. Another example is the delivery of real-time stock market data from one source to many brokerage companies.

  • First octet value range from 224 to 239
  • Number of Networks: N/A
  • Number of Hosts per Network: Multicasting

Class E IP Address Class

Class E IP addresses are not allocated to hosts and are not available for general use. These are reserved for research purposes.

  • First octet value range from 240 to 255
  • Number of Hosts per Network: Research/Reserved/Experimental

Private IP Addresses

Within each network class, there are designated IP address that is reserved specifically for private/internal use only. This IP address cannot be used on Internet-facing devices as that are non-routable. For example, web servers and FTP servers must use non-private IP addresses. However, within your own home or business network, private IP addresses are assigned to your devices (such as workstations, printers, and file servers).

  • Class A Private Range: 10.0.0.0 to 10.255.255.255
  • Automatic Private IP Addressing (APIPA) is a feature with Microsoft Windows -based computers to automatically assign itself an IP address within this range if a Dynamic Host Configuration Protocol (DHCP) server is not available on the network. A DHCP server is a network device that is responsible for assigning IP addresses to devices on the network. At your home, your Internet modem or router likely provides this functionality. In your work place, a Microsoft Windows Server , a network firewall, or some other specialized network device likely provides this functionality for the computer at your work environment.
  • Class B Private Range: 172.16.0.0 to 172.31.255.255
  • Class C Private Range: 192.168.0.0 to 192.168.255.255

Special IP Addresses

  • IP Range: 127.0.0.1 to 127.255.255.255 are network testing addresses (also referred to as loop-back addresses). These are virtual IP address, in that they cannot be assigned to a device. Specifically, the IP 127.0.0.1 is often used to troubleshoot network connectivity issues using the ping command . Specifically, it tests a computer's TCP/IP network software driver to ensure it is working properly. Learn how to use ping 127.0.0.1 to test your computer's TCP/IP network stack.

Summary of IPv4 Classes

Best IP training I have ever seen for IPv4 addressing ...

assignable ip address range

Tips and tricks to use sub-netting!

assignable ip address range

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What are the valid public ip address ranges

There are a number of lists on the web that define all valid public ip addresses ranges but they don't seem to be very accurate.

The most common list Ive found is show below. This list however doesn't include addresses in 191.236.x.x even though there are public web servers in that range.

Is there a definitive and correct list?

  • 1.0.0.0 - 9.255.255.255
  • 11.0.0.0 - 126.255.255.255
  • 129.0.0.0 - 169.253.255.255
  • 169.255.0.0 - 172.15.255.255
  • 172.32.0.0 - 191.0.1.255
  • 192.0.3.0 - 192.88.98.255
  • 192.88.100.0 - 192.167.255.255
  • 192.169.0.0 - 198.17.255.255
  • 198.20.0.0 - 223.255.255.255

PeterJ's user avatar

  • What has your research shown. The list you have isn't complete. –  Ramhound Mar 17, 2016 at 2:08
  • 3 Thats the point of the question –  PeterJ Mar 24, 2016 at 21:45

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assignable ip address range

Given an IP Address and Mask What Are the Assignable IP Addresses in That Network Subnet

assignable ip address range

CCNAs deal with the question, "What IP addresses are in this subnet?" on a regular basis. This section describes how to answer this question if you know how to derive the subnet and broadcast addresses. Simply put, the valid IP addresses that are available for assignment in a subnet are those numerically between the subnet number and the broadcast address.

There is little else to be considered. Certainly, no decimal or binary algorithm needs to be considered for such a simple concept, right? Table 5-19 shows some familiar IP addresses and the corresponding IP addresses in the same subnet.

Table 5-19 Assignable Addresses

The ranges seem obvious. However, look at the 172.100.200.0 subnet. How many assignable IP addresses are in that subnet, and what are those addresses? Is 172.100.200.255 valid? What about 172.100.201.0? In fact, both are valid IP addresses when using 255.255.254.0 as the

mask. The rule is that the subnet numbers (and also the broadcast addresses) are not usable as an IP address. Otherwise, the addresses are assignable to an interface.

Continue reading here: CIDR Private Addressing and NAT

Was this article helpful?

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Readers' Questions

How to find the range of ip address assianble?
To find the range of assignable IP addresses, you need to know the network's IP address and subnet mask. Follow these steps: 1. Determine the network's IP address: This is the base IP address of the network. It can be any address within the network's range, but it typically ends with a zero. For example, if the network IP address is 192.168.1.0, that would be the network's IP address. 2. Determine the subnet mask: The subnet mask determines the size of the network and divides the IP address into network and host portions. It is represented in the form of four sets of numbers separated by periods (e.g., 255.255.255.0). 3. Convert the subnet mask to binary: Each number in the subnet mask can be converted to its binary representation. For example, 255 becomes 11111111 in binary. 4. Count the number of binary zeros in the subnet mask: This will indicate the number of available host addresses within the network. 5. Subtract 2 from the total count: This is because the first and last IP addresses in a network are reserved. The first is the network address, and the last is the broadcast address. 6. Calculate the range: Start with the network's IP address and add the number of usable IP addresses (count - 2) to determine the last assignable IP address. For example, if the network IP address is 192.168.1.0 and the subnet mask is 255.255.255.0, here's how to find the range of assignable IP addresses: Network IP address: 192.168.1.0 Subnet mask: 255.255.255.0 Convert subnet mask to binary: 11111111.11111111.11111111.00000000 Count binary zeros: 8 Subtract 2: 8 - 2 = 6 Range: 192.168.1.1 - 192.168.1.6 So, in this example, the range of assignable IP addresses would be from 192.168.1.1 to 192.168.1.6.
How to identfity how many assignable ip addresses in a given network?
To identify how many assignable IP addresses are in a given network, you will need to know the subnet mask and the IP address range of the network. Using the subnet mask, the IP address range can be divided into different subnets and the total number of assignable IP addresses in each subnet can be calculated.
What is assignable address?
An assignable address is a type of IP address that is allocated to an individual device within a network. This address is usually assigned by a network administrator and is used to identify a device's location within the network.

IP Address Ranges by Country

This page displays the complete IPv4 address ranges organized by country. There are 249 countries listed below, and each link will bring you to a new page containing the respective IP address ranges.

If you are interested to learn more about the ranking of IP addresses allocated for each country, please visit IP Address Reports for details.

Afghanistan

Aland Islands

American Samoa

Antigua and Barbuda

Bolivia (Plurinational State of)

Bonaire, Sint Eustatius and Saba

Bosnia and Herzegovina

Bouvet Island

British Indian Ocean Territory

Brunei Darussalam

Burkina Faso

Cayman Islands

Central African Republic

Congo (Democratic Republic of the)

Cook Islands

Cote d'Ivoire

Dominican Republic

El Salvador

Equatorial Guinea

Falkland Islands (Malvinas)

Faroe Islands

French Guiana

French Polynesia

Guinea-Bissau

Iran (Islamic Republic of)

Isle of Man

Korea (Democratic People's Republic of)

Korea (Republic of)

Lao People's Democratic Republic

Liechtenstein

North Macedonia

Marshall Islands

Micronesia (Federated States of)

Moldova (Republic of)

Netherlands

New Caledonia

New Zealand

Norfolk Island

Northern Mariana Islands

Palestine, State of

Papua New Guinea

Philippines

Puerto Rico

Russian Federation

Saint Barthelemy

Saint Helena, Ascension and Tristan da Cunha

Saint Kitts and Nevis

Saint Lucia

Saint Martin (French Part)

Saint Pierre and Miquelon

Saint Vincent and the Grenadines

Sao Tome and Principe

Saudi Arabia

Sierra Leone

Sint Maarten (Dutch Part)

Solomon Islands

South Africa

South Georgia and the South Sandwich Islands

South Sudan

Svalbard and Jan Mayen

Switzerland

Syrian Arab Republic

Taiwan (Province of China)

Tanzania, United Republic of

Timor-Leste

Trinidad and Tobago

Turkmenistan

Turks and Caicos Islands

United Arab Emirates

United Kingdom of Great Britain and Northern Ireland

United States of America

United States Minor Outlying Islands

Venezuela (Bolivarian Republic of)

Virgin Islands (British)

Virgin Islands (U.S.)

Wallis and Futuna

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COMMENTS

  1. IP Subnet Calculator

    Since the introduction of CIDRs, however, assigning an IP address to a network interface requires both an address and its network mask. Below is a table providing typical subnets for IPv4. This IP subnet calculator covers both IPv4 and IPv6 protocols, providing information such as IP address, network address, subnet mask, IP range, and more.

  2. Subnet Cheat Sheet

    Just scroll or use Ctrl/Cmd + f to find the value you're looking for. Here are the charts, followed by some explanations of what they mean. * /31 is a special case detailed in RFC 3021 where networks with this type of subnet mask can assign two IP addresses as a point-to-point link.

  3. What other IP addresses can/should I use for my home network?

    2,303 3 22 29 1 I generally recommend that folks with home networks just use 192.168.XX./24 where XX is between 10 and 245. perhaps the last two digits of the year of your birth? Any number in that range works. "69 dudes!" -- Bill S Preston Esqr and "Ted" Theodore Logan - Frank Thomas Apr 24, 2015 at 12:50 17

  4. How can you calculate IP address subnet ranges?

    What are the assignable addresses for the 3rd subnet? How would I answer these... All I remember from the procedure is to look at the last number in the Custom subnet mask (192) and do 256 - 192 to get 64 and then use 64 to increment something. But I'm not sure what each question is asking. Please help, and explain step by step for each question.

  5. Subnet Calculator

    The subnet calculator lets you enter a subnet range (CIDR) and see IP address information about that range You can type your range directly in CIDR notation, or use the optional Mask pull-down: 74.125.227./29. 74.125.227.0, then select Optional Mask from dropdown. This is a useful feature for service providers and network operator who ...

  6. Subnet Calculator

    This online calculator helps you determine whether a network has enough hosts. also provides an easy way of translating between CIDR notation and dotted-decimal format if needed. Enter your subnet to get the subnet mask, wildcard mask, network/broadcast address, and number of assignable hosts. You can edit the results and save them on an IP ...

  7. IP Subnet Calculator

    This IP subnet calculator displays comprehensive information about IPv4 networks (e.g., the number of usable hosts, IP ranges, etc.) and IP addresses (e.g., private or public, class, etc.). It's useful for designing networks, troubleshooting, and helping you pass your CompTIA Network+ exam.

  8. Understanding IP Addresses, Subnets, and CIDR Notation ...

    192.168..5 The lowest value in each octet is a 0, and the highest value is 255. We can also express this in binary to get a better idea of how the four octets will look. We will separate each 4 bits by a space for readability and replace the dots with dashes: 1100 0000 - 1010 1000 - 0000 0000 - 0000 0101

  9. IP Subnet Calculator

    IPv4: 192.168..1/24 IPv6: 2002:0BD8::/32 Subnet mask: 192..2./255.255.255. Wildcard subnet mask: 192.0.2.0/0.0.0.255 IPv4 Range: 192.0.2.0-192.0.2.254 IPv6 Range: Currently our calculator doesn't support IPv6 ranges, but it will soon! When you're entering a /X, make sure there's no space inbetween the "/" and the IP Address. Happy Calculating!

  10. How Do IP Addresses Work?

    An IP address is always a set of four numbers like that. Each number can range from 0 to 255. So, the full IP addressing range goes from 0.0.0.0 to 255.255.255.255. The reason each number can only reach up to 255 is that each of the numbers is really an eight digit binary number (sometimes called an octet).

  11. Notes: Networks, Subnets, and CIDR

    The formula to calculate the number of assignable IP address to CIDR networks is similar to classful networking. Subtract the number of network bits from 32. Raise 2 to that power and subtract 2 for the network and broadcast addresses. For example, a /24 network has 2 32-24 - 2 addresses available for host assignment.

  12. Can you manually assign IP address that is out of the DHCP range?

    To actually do this, go Control Panel, Network Connections, right click on the connection you want to set up and go Properties. Click on TCP/IP, and click on properties. Change the radio button from Obtain automatically to 'Use the following IP address'.

  13. List of assigned /8 IPv4 address blocks

    Some large / 8 blocks of IPv4 addresses, the former Class A network blocks, are assigned in whole to single organizations or related groups of organizations, either by the Internet Corporation for Assigned Names and Numbers (ICANN), through the Internet Assigned Numbers Authority (IANA), or a regional Internet registry .

  14. CIDR Calculator for IPv4 addresses

    10.0.0.0/8 172.16../12 192.168../16 Automatic Private IP addresses reserved by IANA. 169.254../16 I have NO DONATE button but if you feel you want to give something you can donate that "something" to Doctors Without Borders by clicking their logo above.

  15. How can i calculate ip address range from subnet mask

    This says that the IP address is 192.168..120. /25 This says that the netmask is 25 bits long. As an IPv4 address is 32 bits, that leaves 7 bits for the address. The lowest IP address in the range is given by masking out the bottom 7 bits, and the highest by adding 127 (=2 7-1) to that.

  16. What Is An IP Range

    An IP range, also known as an Internet Protocol range, is a set of consecutive IP addresses that are grouped together based on specific criteria. In simple terms, it is a range of numbers that represents a block of IP addresses. Each IP address consists of a series of four numbers separated by periods, such as 192.168..1.

  17. Number Resources

    Internet Protocol Version 6 (IPv6) IPv6 Address Space IPv6 Global Unicast Allocations IPv6 Parameters (Parameters described for IPv6, including header types, action codes, etc.) IPv6 Anycast Address Allocations IPv6 Multicast Address Allocations IPv6 Sub-TLA Assignments (DEPRECATED) IANA IPv6 Special Registry

  18. Class A Public & Private IP Address Range

    Private IP Range: 10.0.0.0 to 10.255.255.255 (See Private IP Addresses below for more information) Subnet Mask: 255.0.0.0 (8 bits) Number of Networks: 126 Number of Hosts per Network: 16,777,214 Class B Public & Private IP Address Range Class B addresses are for medium to large sized networks.

  19. What are the valid public ip address ranges

    Ask Question Asked 7 years, 11 months ago Modified 1 year, 5 months ago Viewed 101k times 10 There are a number of lists on the web that define all valid public ip addresses ranges but they don't seem to be very accurate. The most common list Ive found is show below.

  20. PDF CCNA (200-301) Subnetting Practice Excercises

    What is the range of assignable IP addresses for a subnet containing an IP address of 172.16.1.10 /19? 172.16..1 - 172.16.31.254 172.16..1 - 172.16.63.254 172.16.. - 172.16.31.255 172.16..1 - 172.16.31.255 172.16.. - 172.16.63.254 Question #2 You are assigning IP addresses to hosts in the 192.168.4. /26 subnet.

  21. Solved Classless Inter-Domain Routing (CIDR) is a method for

    b) What is the assignable IP address range? c) What is the subnet mask? There are 2 steps to solve this one. Expert-verified Step 1 To answer your questions about the CIDR address 168.2.44.0/22: a) How many assignable IP addresses are there? View the full answer Step 2 Unlock Answer Unlock Previous question Next question

  22. Given an IP Address and Mask What Are the Assignable IP Addresses in

    Last Updated on Sun, 27 Aug 2023 | Interface Serial CCNAs deal with the question, "What IP addresses are in this subnet?" on a regular basis. This section describes how to answer this question if you know how to derive the subnet and broadcast addresses.

  23. IP Address Ranges by Country

    There are 249 countries listed below, and each link will bring you to a new page containing the respective IP address ranges. If you are interested to learn more about the ranking of IP addresses allocated for each country, please visit IP Address Reports for details. Afghanistan. Aland Islands. Albania.