Hi list,

I have a KISS-attached TNC that I use primarily for outgoing AX.25 layer 
connections, and for TCP/IP services listening on ax0. I am not running ax25d 
or any software listening on an AX.25-family socket. I've noticed on several 
occasions that if somebody sends an SABM to my station the connection will be 
accepted. The data doesn't go anywhere. Eventually they DISC and my station 
replies UA. I am left with a lingering socket which means I can't communicate 
with that station any more.

1: fm VK7BEN-1 to VK7NTK-1 ctl SABM+ 10:29:59
1: fm VK7NTK-1 to VK7BEN-1 ctl UA- 10:29:59
... (snip "I" and "RR" frames as remote user sends data) ...
1: fm VK7BEN-1 to VK7NTK-1 ctl DISC+ 10:30:36
1: fm VK7NTK-1 to VK7BEN-1 ctl UA- 10:30:36

When I come along later:

$ netstat -a -A ax25
Active AX.25 sockets
Dest       Source     Device  State        Vr/Vs    Send-Q  Recv-Q
VK7BEN-1   VK7NTK-1   ax0     LISTENING    005/000  0       0

$ sudo axcall 1 vk7ben-1
GW4PTS AX.25 Connect v1.11
Trying...

connect: Address already in use

I can attempt to kill it - the remote station responds that it's in 
disconnected mode, but I am still left with this odd "LISTENING" socket.

$ sudo axctl 1 VK7BEN-1 VK7NTK-1 kill

1: fm VK7NTK-1 to VK7BEN-1 ctl DISC+ 11:18:56
1: fm VK7BEN-1 to VK7NTK-1 ctl DM- 11:18:57

$ netstat -a -A ax25
Active AX.25 sockets
Dest       Source     Device  State        Vr/Vs    Send-Q  Recv-Q
VK7BEN-1   VK7NTK-1   ax0     LISTENING    005/000  0       0

I was wondering if anyone could help me understand why the connection gets 
accepted in the first place, and if there is a way to clean up the lingering 
connection?

Regards,

Tom
VK7NTK

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