1st. Is there a Yapp implementation under Linux????
Not sure. Once you get used to FTP you'll never go back anyway. :-)
2nd. If I have AX25 running on the linux box, what do I need to do
to
start supporting IP traffic? It is running fine for AX25
connections.
Read the HOWTO. Basically you need to get an IP address from your
local coordinator, ifconfig to connect that address to an AX25
interface, and add routes describing how you want outgoing traffic
routed (which neighboring systems route which subnets). It's pretty
simple, you have the hard part done already.
www.cc.gatech.edu/linux/LDP and follow the links to the howto.