Debian AX.25 mini-HOWTO

Here's an example on setting up an AX.25 network interface in Debian GNU/Linux. This works for Ubuntu too.

Hardware configuration

I've chosen to label my combination of rig and TNC as "the fubar setup".

Software configuration

Install AX.25 tools with your favorite package manager.

aptitude install ax25-tools

Configure a port and set parameters for it.

# /etc/ax25/axports
#
# The format of this file is:
#
# name callsign speed paclen window description
#
fubar	MYCALL-15	19200	255	2	144,800 MHz APRS

Configure a network interface for the port. It is done by adding something like this into /etc/network/interfaces file.

# The fubar network interface.
manual ax0
iface ax0 inet static
	address 10.36.99.1
	netmask 255.255.255.0
	network 10.36.99.0
	broadcast 10.36.99.255
	# Bind to the port.
	hwaddress ax25 MYCALL-15
	# Create the port before starting the iface.
	pre-up kissattach /dev/ttyS0 fubar 10.36.99.1
	# 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

Make sure that no unwanted traffic goes out via the interface. If some program sends stuff there, you have at least the following options to prevent it.
- If you don't need the program, use your favorite package manager to remove it.
- If removing is not an option, configure the daemon so that it won't bind to ax0 or the ip you chose for it.
- If the daemon can't be configured, use firewall to block the unwanted traffic.
For example Samba likes to broadcast to every interface. This is not cool, since we usually don't want to hear Samba on the packet radio frequency. If you don't need Samba, best option would be to use your favorite package manager to remove it.
```
aptitude remove samba
```

Usage

Now you should be able to start the interface by saying

sudo ifup ax0

and stop it by saying

sudo ifdown ax0

If you want the interface to start at boot, change the line

manual ax0

into

auto ax0

in /etc/network/intefaces and the magic should happen.

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