How my AX25 system is setup.
I have written the following scripts which are started after the main
boot proccess has finished, as we all know rc.local is the last file to
be executed on what i belive is all distribtutions.
# /etc/rc.d/rc.local: Local system initialization script.
# Put any local setup commands in here:
if [ -f /etc/rc.d/rc.ax25 ]; then
rc.ax25 starts the ball rolling, there are a number of other files
called one after another, basicly as follows.
rc.ax25 starts the basic AX25 and NETROM system, loads the modules
if they are not there, checks to see that the interfaces are not up
before attempting to attach them, this because the script is written
not only to attach the interfaces but to detach them as well.
After attaching the NETROM interface it calls other scripts.
The chain of events is;
rc.local gets read, the line if [ -f
means if the file /etc/rc.d/rc.ax25 is found "then" execute it.
One could use if [ -x
Which means if the file rc.ax25 is executable "then" execute it.
rc.ax25 has as its first line;
# Get config.
It means read the file /etc/rc.d/axdefs
/etc/rc.d/axdefs is the file containing PATH's, callsigns, ipaddresses,
MAC addres for a BPQ interface, MTU + lots more.
No doubt some who read these pages will not be able to understand a
thing. So i decided to gove a few examples in "Keep It Simple Stupid"
terms, now thats not meant as a comment, that is just the "kiss" method.
Attach one TNC to com1 (/dev/ttyS0)
/sbin/kissattach -l -m256 /dev/ttyS0 ax0 220.127.116.11
For the above axports would be.
ax0 ZZ1ZZ-15 4800 256 4 radio_port
Add routing, the whole 44 network.
There is no need to, ifconfig has assigned a netmask of 255.0.0.0
it sees this as a reason to add a defult route to the network (44)
on that interface, which means if you attach other intefaces without
using ifconfig to change the netmask a default route WILL be assigned
to every interface.
If you want to use 255.0.0.0 as a netmask, do the following after every
ax25 interface is upped.
route del -net 18.104.22.168 netmask 255.0.0.0 ifc
Where 'ifc' is the name of the interface which has just been attached.
Or add a route to 22.214.171.124
route add 126.96.36.199 ax0
It is advisable to use the mss, window and irtt under route, why?.
Via route we can set a window size, meaning state how many packets we
wish to use in one transmission.
MSS is the maximum transmission unit, why it has to be called mss still
is a mystory, MSS = Maximun Segment Size.
IRTT is the Initial Round Trip Time.
route add 188.8.131.52 mss 256 window 944 irtt 6000 ax0
sets a route to 184.108.40.206 with a MTU of 256 and allows 4 packets per
transmission and the link will be started with a waittime of 6 seconds
The output of '/sbin/ifconfig ax0' should now like like;
ax0 Link encap:AMPR AX.25 HWaddr ZZ1ZZ-15
inet addr:220.127.116.11 Mask:255.0.0.0
UP RUNNING MTU:256 Metric:1
RX packets:123 errors:0 dropped:0 overruns:0 frame:0
TX packets:456 errors:0 dropped:0 overruns:0 carrier:0
The routing table for ax0 will look something like;
18.104.22.168 0.0.0.0 255.255.255.255 UH 256 944 6000 ax0
Richard Adams PA3GCU,