The AX.25 software is comprised of three components: the kernel source, the network configuration tools and the utility programs.
AX.25 support in the Linux kernel has been fairly stable since the 2.2 series of kernel versions. This document assumes you are using the most recent kernel, which as the time of writing was 2.4.9.
Software versions listed in this document were the latest at the time of writing, but are subject to change. Check for newer versions when downloading them.
The kernel source can be found at www.kernel.org and ftp.kernel.org. For the 2.4.9 kernel it would be downloaded from ftp://ftp.kernel.org/pub/linux/kernel/v2.4/linux-2.4.9.tar.gz.
The latest release of the standard Linux network tools support AX.25 and NET/ROM and can be found at http://www.tazenda.demon.co.uk/phil/net-tools.
The latest ipchains package can be found at http://netfilter.filewatcher.org/ipchains.
It is usually not necessary to download and install these as any recent Linux distribution should include them.
The old ax25-utils used with the 2.0 and 2.1 kernels is now obsolete and has been replaced with new packages hosted on SourceForge at http://sourceforge.net/projects/hams.
The software is distributed as three packages: the AX.25 library, tools, and applications. At the time of writing the most recent versions were the following:
If you want to use APRS you can download aprsd and aprsdigi: