IPv4 Octet Extraction (Capture Groups) Regex for Python

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching ipv4 octet extraction (capture groups), 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 Octet Extraction (Capture Groups)
# ReDoS-safe | RegexVault — Web & Network > IPv4

import re

ipv4_octet_extraction_capture_groups_pattern = re.compile(r'^((?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9]))\.((?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9]))\.((?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9]))\.((?:25[0-5]|2[0-4][0-9]|1[0-9]{2}|[1-9][0-9]|[0-9]))$')

def validate_ipv4_octet_extraction_capture_groups(value: str) -> bool:
    return bool(ipv4_octet_extraction_capture_groups_pattern.fullmatch(value))

# Example
print(validate_ipv4_octet_extraction_capture_groups("192.168.1.1"))  # 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

Groups 1–4 capture each octet as a string. Cast to integer after extraction. Python users can use (?P<octet1>...) syntax for named groups.