Check If a String is a valid IP Address in Python

In this article, we will discuss three different ways to check if a string is a valid IP Address in Python.

Table of Contents

Check If a String is a valid IP Address using Regex

In Python, the regex module provides a member function search(), which accepts a string and a regex pattern as arguments. Then it looks for the substrings in the given string based on that regex pattern. If the pattern is found then it returns a Match object, otherwise returns None. We are going to use the same regex.search() function with a regex pattern –> “^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$”. This regex pattern looks for a valid IP Address string. It verifies that the string contains four numbers (three digit), seperated by dots. Then we need to check that each of this number is in a range of 0 to 255.

We have created a separate function, that will use this regex pattern to check if a given string is valid or not i.e.

import re 

def valid_IP_Address(sample_str):
    ''' Returns True if given string is a
        valid IP Address, else returns False'''
    result = True
    match_obj = re.search( r"^(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})$", sample_str)
    if  match_obj is None:
        result = False
    else:
        for value in match_obj.groups():
            if int(value) > 255:
                result = False
                break
    return result

Let’s use this function to with certain strings to verify if they contain a valid IP Address. For example,

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10 Sec

Lambda Functions in Python

def test_func(ip_str):
    if valid_IP_Address(ip_str):
        print(f'Yes, string "%s" is a valid Ip Address' % (ip_str))
    else:
        print(f'No, string "%s" is not a valid Ip Address' % (ip_str))
    

test_func("192.168.1.1")
test_func("1234.168.1.1")
test_func("192.168.1.ccc")
test_func("0.0.0.0")
test_func("255.255.255.255")
test_func("256.256.256.256")
test_func("300.300.300.300")
test_func("192.f18.1.1")

Output:

Yes, string "192.168.1.1" is a valid Ip Address
No, string "1234.168.1.1" is not a valid Ip Address
No, string "192.168.1.ccc" is not a valid Ip Address
Yes, string "0.0.0.0" is a valid Ip Address
Yes, string "255.255.255.255" is a valid Ip Address
No, string "256.256.256.256" is not a valid Ip Address
No, string "300.300.300.300" is not a valid Ip Address
No, string "192.f18.1.1" is not a valid Ip Address

In the regex pattern we matched each number in the IP Address as a separate group. If the regex match is valid, we check that the each value in the four groups is from range 0 to 255.

Check If a String is a valid IP Address using ipaddress module

We can use the ipaddress module in Python, to verify if a string is a valid IP or not. If the ipaddress module is not installed, then you can install it using command,

pip install ipaddress

The ipaddress module provides a function ip_network(str). It accepts the IP Addtess string as argument and returns object of the correct type if given string is a valid IP Address. It will raise ValueError, if the string passed isn’t either a v4 or a v6 IP Address.

We have created a function that uses the ipaddress module to verify if a string is a valid IP Address or not,

import ipaddress

def is_valid_IPAddress(sample_str):
    ''' Returns True if given string is a
        valid IP Address, else returns False'''
    result = True
    try:
        ipaddress.ip_network(sample_str)
    except:
        result = False
    return result

Let’s use this function to with certain strings to verify if they contain a valid IP Address. For example,

def test_func(ip_str):
    if is_valid_IPAddress(ip_str):
        print(f'Yes, string "%s" is a valid Ip Address' % (ip_str))
    else:
        print(f'No, string "%s" is not a valid Ip Address' % (ip_str))
    

test_func("192.168.1.1")
test_func("1234.168.1.1")
test_func("192.168.1.ccc")
test_func("0.0.0.0")
test_func("255.255.255.255")
test_func("256.256.256.256")
test_func("300.300.300.300")
test_func("192.f18.1.1")

Output:

Yes, string "192.168.1.1" is a valid Ip Address
No, string "1234.168.1.1" is not a valid Ip Address
No, string "192.168.1.ccc" is not a valid Ip Address
Yes, string "0.0.0.0" is a valid Ip Address
Yes, string "255.255.255.255" is a valid Ip Address
No, string "256.256.256.256" is not a valid Ip Address
No, string "300.300.300.300" is not a valid Ip Address
No, string "192.f18.1.1" is not a valid Ip Address

Check If a String is a valid IP Address using socket module

Python provides a socket module, which has a function inet_aton(). It converts a string format IPv4 address to a 32-bit packed binary format. If the given string is not a valid IP Address, it raises a error.

We have created a function that uses the socket module to verify if a string is a valid IP Address or not,

import socket

def is_valid_IP_Address(ip_str):
    ''' Returns True if given string is a
        valid IP Address, else returns False'''
    result = True
    try:
        socket.inet_aton(ip_str)
    except socket.error:
        result = False
    return result

Let’s use this function to with certain strings to verify if they contain a valid IP Address. For example,

def test_func(ip_str):
    if is_valid_IP_Address(ip_str):
        print(f'Yes, string "%s" is a valid Ip Address' % (ip_str))
    else:
        print(f'No, string "%s" is not a valid Ip Address' % (ip_str))
    

test_func("192.168.1.1")
test_func("1234.168.1.1")
test_func("192.168.1.ccc")
test_func("0.0.0.0")
test_func("255.255.255.255")
test_func("256.256.256.256")
test_func("300.300.300.300")
test_func("192.f18.1.1")

Output:

Yes, string "192.168.1.1" is a valid Ip Address
No, string "1234.168.1.1" is not a valid Ip Address
No, string "192.168.1.ccc" is not a valid Ip Address
Yes, string "0.0.0.0" is a valid Ip Address
Yes, string "255.255.255.255" is a valid Ip Address
No, string "256.256.256.256" is not a valid Ip Address
No, string "300.300.300.300" is not a valid Ip Address
No, string "192.f18.1.1" is not a valid Ip Address

Summary

We learned about three different ways to validate if a string contains a valid IP Address or not.