Re: telnet/ssh disconnects... Possible NAT teardown?

["Christopher K. Johnson" <ckjohnson@xxxxxxx>]

Jeremy wrote:

> Ok, I'm at home now, and i tried telneting in from another computer on the
> network....   It works fine.  No disconnects.
>
> I'm using Road-Runner (Cable modem) to connect to the internet, the linux PC in
> question is the router (2 NIC cards, one to cable modem, other to LAN).
>
> Is it possible the cable modem is the cause?  I don't understand what could be
> wrong.
>
> -Jeremy
>
>  
This is a common problem with ssh connections through firewalls.
I avoid this problem by placing the following perl script in my path 
(either world executable in /usr/local/bin for any users , or user 
executable in my own ~/bin/ directory) and I name it "dot".  Then either 
execute dot when leaving an ssh session alone for a while, or run it in 
the background if it is not too disruptive of what you are doing.   Just 
ctrl-c with dot in the foregrond to stop it.

#!/usr/bin/perl
# Simple keep-alive script when port forwarding via ssh through firewall
# Otherwise the TCP connections in fw table may timeout.
$|=1;
$i=0;
while (true){
 $i++;
 if ($i>60) {
   print("\n.");
   $i=1;
 } else{
   print(".");
 }
sleep 60;
}

Enjoy!

--
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  "Spend less!  Do more!  Go Open Source..." -- Dirigo.net
  Chris Johnson, RHCE #807000448202021