SSHD – Port Forwarding Problem.

To connect to my work PC I run Bitvise’s Tunnelier on my work PC and SSHD at home. My work PC then connects to my home machine and “asks” it to forward traffic from certain ports over the Internet to work. The idea being that I can then RDP from home to work using the SSH tunnel.

Now this all works fine, but I found that if the connection at work died then when work tried to reconnect the port forwarding failed with Received disconnect from <IP>: 11: Server denied request for client-side server-2-client forwarding on 127.0.0.1:3389.

What this message meant was that my home PC still thought that the old connection was alive and was honouring the old request to forward port 3389.

The only way I had around this was to restart my machine/all the networking services… until now. Now I just do sudo iptables -P FORWARD DROP and life is peachy.

I have not yet worked out fully what this has done – as it is just my machine and no other forwards are in place I am not concerned, but if you are not the sole user of your box then I would not use it as-is without expecting to upset a few people.