AX.25 in Debian

Situation

You have connected a 6PACK TNC to your serial port (and a radio to the tnc) and want to transmit IP traffic.

Installation
apt-get install ax25-tools

Configuration
# /etc/ax25/axports
#
# The format of this file is:
#
# name  callsign   speed  paclen  window  description
#
foobar  MYCALL-15  19200  255     2       438,450 MHz My Digipeater

Note: Speed is not the hf-baudrate but the serial baudrate.

Interface Configuration
Add this to /etc/network/interfaces 
# The foobar network interface.
manual ax0
iface ax0 inet static
	address 44.37.100.3
	netmask 255.255.255.0
	network 44.37.100.0
	broadcast 44.37.100.255
	# Bind to the port.
	hwaddress ax25 MYCALL-15
	# Create the port before starting the iface.
	pre-up kissattach -6 /dev/ttyS0 foobar 44.37.100.3
	# Delete the port after stopping the iface. Make sure that it dies
	# and lock file is removed.
	post-down pkill kissattach || pkill -9 kissattach ; rm -f /var/lock/LCK..ttyS0

Usage
Start the interface using 
ifup ax0

Stop the interface using 
ifdown ax0

For automatic start on boot, change manual ax0 into auto ax0 in /etc/network/interfaces.