Month: January 2026

IPs, Python style pt. 1

Hello everybody,

Welcome back, and I hope you all had a wonderfully festive holiday season! I’m definitely ready to share some juicy programming content with you all in 2026-which will include the milestone 200th post!

To start off my 2026 slate of content, let’s explore IP addresses, Python style. More specifically, let’s explore some of the capabilities of Python’s ipaddress module!

Let’s get stuff started!

Before we dive in to all the fun Python IP address stuff, let’s first get ourselves set up on the IDE.

First things first, let’s pip install ipaddress (this will be the only module we’ll need for this lesson):

!pip install ipaddress

What kind of IP address are we looking at?

Once we’ve installed the ipaddress module, let’s explore its capabilities. First off, let’s see how IP address objects are created:

import ipaddress
ipaddress.ip_address('192.168.1.1')

IPv4Address('192.168.1.1')

By using the aptly-named ipaddress.ip_address method, you can return either an IPv4Address or IPv6Address object, depending on what you pass into the method.

Let’s try this method with an IPv6 address:

ipaddress.ip_address('2001:db8::1')

IPv6Address('2001:db8::1')

In this example, we pass in the IPv6 address 2001:db8::1 and the ip_address() method returns the IP address as an IPv6Address object.

  • The IPv6 address 2001:db8::1 is IPv6 shorthand for 2001:0db8:0000:0000:0000:0000:0000:0001. IPv6 shorthand tends to leave out any leading 0s in any section of the IP address along with using :: as common shorthand for 0000:0000:0000:0000:0000.

Is this IP address in the network?

Next up, let’s not only create an IP network object but also check if it’s in a network:

#creating the IP network
NETWORK = ipaddress.ip_network('10.0.0.0/16')

#creating IP address object
IPV4 = ipaddress.ip_address('10.1.13.38')

print(IPV4 in NETWORK)

False

From the IP address package, we can create a NETWORK object that represents an IP address network along with an IPv4 address object. For this example, we’ll use the 10.0.0.0 IP network with subnet /16 and check if the IP address 10.1.13.38 is in the network. In this case, the IP address isn’t in the network.

How many IPs are in my network?

Now that we know how to create a network object, let’s see how we can find out all the possible hosts in the IP network we just created:

for host in NETWORK.hosts():
    print(host)

Streaming output truncated to the last 5000 lines.
10.0.236.119
10.0.236.120
10.0.236.121
10.0.236.122
10.0.236.123
10.0.236.124
10.0.236.125
10.0.236.126
10.0.236.127
10.0.236.128
(output truncated for brevity)

It’s quite simple actually. All we need to do is use a standard Python for loop and iterate through the hosts property of the network object we created.

Notice the line at the top of the output-Streaming output truncated to the last 5000 lines. Even though we only see 5000 of the possible IP addresses, there are definitely more. How can we know how many IP addresses are in a network?

So, how many IP addresses are in a network?

How can we find out exactly how many IP addresses are in a given network? Here’s a simple formula to find out:

Yes, this is the formula to find out how many IP addresses can exist on a given network. Simply take 2 to the power of (32-CIDR) to get the answer-CIDR referring to the subnet mask in CIDR notation.

For instance, /16 contains 65,536 possible IP addresses while /24 has room for only 256 possible IP addresses. Also, in case you were wondering, networks with a /1 subnet can be quite massive-leaving room for 2,147,483,648 (roughly 2.1 billion) possible IP addresses. On the other hand, networks with a /31 subnet only leave room for 2 possible IP address. Then again, it’s highly unlikely networks would be so small or so big-subnets between /8 and /24 tend to be the most common.

Here’s the GitHub notebook for this post-https://github.com/mfletcher2021/blogcode/blob/main/IP_addresses.ipynb

Thanks for reading, and be sure to check out my next post where we will explore more uses of Python’s handy ipaddress module. I’m certainly looking forward to all the juicy techie content I have planned for you all in 2026!