MAC Address Format Standard #

Rule #

All MAC addresses in Deevnet inventory and configuration MUST use:

lowercase hex digits (a-f, not A-F)
Colon separators (:, not -)

Examples #

Correct:

mac: "bc:24:11:2e:26:4e"
mac: "dc:a6:32:c3:b4:bc"

Incorrect:

mac: "BC:24:11:2E:26:4E"  # uppercase
mac: "bc-24-11-2e-26-4e"  # dashes

Rationale #

Deevnet uses lowercase to match Unix tooling conventions:

ifconfig, ip link, and most Linux utilities display MAC addresses in lowercase
Copy-paste from system output works without transformation
Consistent with what operators see when troubleshooting

IEEE 802 and RFC 7042 documentation examples use uppercase, but this is a documentation convention rather than a technical requirement. We prioritize practical alignment with the Unix ecosystem over formal documentation style.

Runtime Normalization #

Some downstream systems expect specific formats:

The gateway DHCP configuration normalizes to uppercase at runtime
Network boot infrastructure generates both upper and lowercase bootloader config filenames to handle firmware variations

These transformations happen automatically. The source of truth in inventory remains lowercase.

Location #

MAC addresses belong in infrastructure.interfaces.<name>.mac as part of host identity per the Identity vs Intent standard.

MAC Namespace Specification - Defines the semantic structure of MAC addresses (environment, role, instance encoding)

This document defines how MAC addresses are formatted. The namespace specification defines what values they contain.