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6. ax25-config - behind the scenes

Ax25-config creates (and overwrites!) a whole bunch of configuration files. If ax25-config has configured your system so it works at a basic level you might want to customize the setup. In this section I explain what files ax25-config does creates and what they are used for. Keep in mind that after changing these files you SHOULD NOT run ax25-config again, because it will overwrite your changes! You might consider to improve ax25-config itself to support your configuration, though. Send us patches!


This file describes each port. ax25-config defines each port with the same name as the corresponding network-device. This makes configuration easier and ensures compatibility between older and newer versions of the ax25 tools and utilities. The axports file is documented in the axports manual page, to view it, type "man 5 axports" in a shell window or man:axports in the kdehelp window.


This is a shell-script which contains the necessary commands to configure the ax25 subsystem. Typically it first loads the appropriate kernel-modules (e.g. the baycom serial driver):

# Module einbinden 
/sbin/modprobe baycom_ser_fdx 

Next it configures the driver using sethdlc, or it attaches a kissinterface using kissattach. You find further information about how this works in the sethdlc, kissattach or yamcfg manpages. This is how the serial baycom modem is configured:

# Konfiguration des Modems:
#   Der Stern hinter "ser12" bedeutet, dañ Software-DCD verwendet wird,
#   Ohne Stern wird Hardware-DCD erwartet.
sethdlc -p -i bcsf0 mode "ser12*" io 0x378 

Then it configures the ax.25 channel access parameters, this is done using sethdlc(8) for baycom style modems and axparms(8) for others:

# Parameter einstellen: P=128, W=30, TX-Delay=200
sethdlc -i bcsf0 -a txd 200 slot 30 ppersist 128 half

Last but not least the newly created devices is configured using the standard linux ifconfig(8) command:

# Modem im System anmelden und mit dem Rufzeichen verknØpfen
/sbin/ifconfig bcsf0 hw ax25 DG4IAD up
# Port "bcsf0" als NetzwerkgerÄt "bcsf0" anmelden mit IP
/sbin/ifconfig bcsf0 netmask \
               broadcast up

At the end it starts listen(1) and ax25d(8) if you did enable them. Their "process ids" are stored in /var/run so ax25-down can shut them down properly.

# Kanal-Monitor auf Terminal 11 starten
/usr/bin/listen -a -p bcsf0 > /dev/tty11 &
echo $! > /var/run/


This script shuts the ax25-subsystem down. It should be run before halting your system. The first two blocks are some black shell magic to find the right listen and ax25d processes and shoot them. Then the interface is shut down using ifconfig(8) and at the end the kernelmodules are removed using modprobe -r.


This file is the configuration for ax25d(8). ax25d is a daemon (=a program running in the background without being visible on the screen) which listens for incoming ax25 connections and starts arbitrary programs for this connection. You can use this to have a node or a personal message system which can be connected over packet. ax25-config does not currently support pms or node, ax25d is only used to start axspawn(8). A detailed description of the ax25d.conf configuration file is given in the ax25d.conf(5) manual page.


This is the configuration file of axspawn. axspawn is used to enable other people to log in to your system over packet radio. It can even create new accounts for unknown callsigns. This is very problematic with regard of security. Don't enable axspawn if your machine isn't a dedicated for ham radio.

/etc/ax25/nrports and /etc/ax25/rsports

ax25-config create these files but net/rom and rose support is not implemented yet (although netrom might be trivially to support). Have a look into the nrports(5) and rsports(5) manual pages if you want to know more.


This file is used by ax25-config internally. The fileformat is likely to change soon and it is overwritten by ax25-config, therefore I won't describe it here.

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