IPv4 Address with Port Regex for Python

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching ipv4 address with port, ported and verified for Python. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.

Python Implementation

# IPv4 Address with Port
# ReDoS-safe | RegexVault — Web & Network > IPv4

import re

ipv4_address_with_port_pattern = re.compile(r'^(?:(?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])\.){3}(?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9])(?::(?:6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3}))?$')

def validate_ipv4_address_with_port(value: str) -> bool:
    return bool(ipv4_address_with_port_pattern.fullmatch(value))

# Example
print(validate_ipv4_address_with_port("192.168.1.1:8080"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > IPv4 category and carries a ReDoS-safe certification. That matters for Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

Port 0 is excluded as it is not a valid user-assigned port. The strict port alternation covers 1–65535 exactly.