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 has;
#!/bin/sh
#
# /etc/rc.d/rc.local: Local system initialization script.
#
# Put any local setup commands in here:
if [ -f /etc/rc.d/rc.ax25 ]; then
/etc/rc.d/rc.ax25 up
fi
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. . /etc/rc.d/axdefs
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.
- /etc/rc.d/axdefs.
rc.ax25 then continues as shown in the next link.- /etc/rc.d/rc.ax25.
You will have seen that in rc.ax25 other files get called they are.- /etc/rc.d/rc.tunnel
attaches the tunnel interface.
To be able to use the tunnel interface you will need the ip2route
package, it should be available on most linux ftp mirror sites.- /etc/rc.d/rc.ax0
attaches the ax0 interface for the tunnel. - /etc/rc.d/rc.scc
attaches the scc interface. - Configuration
files axports etc..
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 44.123.123.123
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 44.0.0.0 netmask 255.0.0.0 ifc
Where 'ifc' is the name of the interface which has just been attached.
Or add a route to 44.123.123.1
route add 44.123.123.1 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 44.123.123.1 mss 256 window 944 irtt 6000 ax0
sets a route to 44.123.123.1 with a MTU of 256 and allows 4 packets per
transmission and the link will be started with a waittime of 6 seconds
before retransmitting.
The output of '/sbin/ifconfig ax0' should now like like;
ax0 Link encap:AMPR AX.25 HWaddr ZZ1ZZ-15 inet addr:44.123.123.123 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 collisions:0 txqueuelen:10
The routing table for ax0 will look something like;44.123.123.1 0.0.0.0 255.255.255.255 UH 256 944 6000 ax0Richard Adams PA3GCU, E-mail: pa3gcu@zeelandnet.nl