isithran

isithran@social.lkw.tf

HamRadio operator (mainly packet data, microwave links, hamnet), λ＜6m. High energy physics, timekeeping and unrelated stuff.

She/Her 🏳️‍⚧️

France

https://gensokyo.tf/links ✔

friendica (DFRN) - Link to source

isithran

Friday, January 30, 2026, 10:15 PM from Tusky

isithran
Friday, January 30, 2026, 10:15 PM from Tusky

Having a dissector for a protocol which spec is not yet completed, nor public: check.

AX.25 Authentication Header

## Status of this Memo
This document specifies an Amateur Radio protocol, and requests discussion and suggestions for improvements. Distribution of this memo is unlimited.

## Copyright Notice

Copyright (C) 2026 Célestine Gramaize F4HOF

## Introduction

The AX.25 Authentication Header (AX.AH) is used to provide connectionless integrity and data origin authentication for AX.25 datagram (hereafter referred to as just "authentication"), and to provide protection the default calls for the sender to increment the Sequence Number against replays. AX.AH provides authentication for as much of the AX.25 header as possible, as well as for upper level protocol data. However, some AX.25 header fields may change in transit and the value of these fields, when the packet arrives at the receiver, may not be predictable by the sender. The values of such fields cannot be protected by AX.AH.

The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this document, are to be interpreted as described in [RFC 2119}(https://datatracker.ietf.org/doc/html/rfc2119).

Security services can be provided between a pair of communicating hosts, between a pair of communicating security gateways, or between a security gateway and a host.

A Wireshark screenshot depicting an AX.25 capture in which an AXSec packet is selected.

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