Hi

I've installed a Slackware box at work which I can access with SSH from the local network, but need to SSH into it from home.

There is a Thomson TG585v7 ADSL modem/router/wireless all-in-one connected to the phone line. Then there is an SMC-EZ1024DT switch plugged into ethernet port 1 on the Thomson.

I have disabled the Firewall on the Thomson and disabled any software firewalls. But whenever I try (from work) the ShieldsUP port probe at www.grc.com I get a perfect "TruStealth" rating.

I have tried plugging straight into the Thomson, using different workstations on the network, even unplugging the switch completely - still can't get a single port to show as open.

Am I missing something? Is it possible the ISP blocks traffic before it even gets here? What else can I try? (I've done this at home and didn't have any problems...)

It's possible that your workplace is running a firewall on their internal network. Every connection to or from your work would have to bypass it.

Its possible, but I don't know where it could be.

I've tried disconnecting virtually everything from the (small) network for testing - no luck so far.

Okay, I've made some progress. I have managed to open up port 80 and access the web server on my laptop. But I tried the same thing with SSH and port 22 still shows as 'stealth'.

I'll keep trying things...

Is the router a NAT router? You need to forward port 22 to your slackware machine. Otherwise the router will not know which host to forward it to and simply drop the connection. If you try to ssh to the router without port forwarding, you are actually trying to log into an ssh service running on the router itself.

Also make sure that the firewall on the slackware computer has port 22 open. Another thing is to verify that the ssh daemon is running. If you can ssh in on another machine on the lan, you know that it is.

If your router can forward a port to another port, consider using a higher order port, and having it forwarded to your slackware's IP at port 22. E.G. forward port 1025 -> slackware IP:22. Using a non-standard port for ssh will reduce the number of script kiddie brute force attacks against ssh. Also be sure to read the manpage for sshd_config. There are several options you want to make ssh more secure.

The router does have NAT abilities, but I think it's designed as a home router. In the web interface it has things like "Game and Application Sharing", which is how I got the web server to be visible from outside. I tried setting up SSH the same way, but the port still shows as stealth.

SSH daemon is running, I can log in from a laptop on the LAN.

I'll keep trying things in the router web interface...