MAC Address (Cisco Dot-Separated) Regex for Python

What this pattern does

This page provides a well-structured, multi-part regular expression for matching mac address (cisco dot-separated), 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

# MAC Address (Cisco Dot-Separated)
# ReDoS-safe | RegexVault — Web & Network > MAC Address

import re

mac_address_cisco_dotseparated_pattern = re.compile(r'^[0-9a-fA-F]{4}\.[0-9a-fA-F]{4}\.[0-9a-fA-F]{4}$')

def validate_mac_address_cisco_dotseparated(value: str) -> bool:
    return bool(mac_address_cisco_dotseparated_pattern.fullmatch(value))

# Example
print(validate_mac_address_cisco_dotseparated("001a.2b3c.4d5e"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Web & Network > MAC Address 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

Cisco IOS, Catalyst switches, and Wireshark commonly use this format. The same 48 bits are encoded as 3x4 hex digits rather than 6x2.