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Regex for IPv4 Address

Regex Pattern

^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$

Validates a well-formed IPv4 address (0-255 in each octet)

Quick Answer

The regex pattern for ipv4 address is `^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$`. Validates a well-formed IPv4 address (0-255 in each octet). This works in JavaScript, Python, Ruby, PHP, Java, and most regex engines that support PCRE syntax.

Test Examples

InputResult
192.168.1.1✓ Matches
255.255.255.255✓ Matches
10.0.0.1✓ Matches
127.0.0.1✓ Matches
256.1.1.1✗ No match
192.168.1✗ No match
192.168.1.1.1✗ No match
abc.def.ghi.jkl✗ No match

Code Examples

javascript

const regex = /^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/;
const isValid = regex.test(value);

python

import re
pattern = r'^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$'
if re.match(pattern, value):
    print("valid")

ruby

pattern = /^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/
if value =~ pattern
  puts "valid"
end

php

if (preg_match('/^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$/', $value)) {
    echo "valid";
}

java

String pattern = "^((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$";
boolean isValid = value.matches(pattern);

Frequently Asked Questions

Related Regex Patterns

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