🖥️

Regex for IPv4 Address

Matches a valid IPv4 address (0-255 blocks).

The 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]?)$/

Test in Visualizer ↗

✅ Matches

✓ 192.168.1.1
✓ 255.255.255.0

❌ Non-Matches

✕ 256.1.1.1
✕ 192.168.1
✕ 192.168.1.1.1

Implement in your Code

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]?)$/;
regex.test('192.168.1.1');

python

import re
regex = re.compile(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]?)$')
bool(regex.match('192.168.1.1'))

import "regexp"
matched, _ := regexp.MatchString(`^(?:(?: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]?)$`, "192.168.1.1")

rust

use regex::Regex;
let re = Regex::new(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]?)$").unwrap();
re.is_match("192.168.1.1")