Okay, I configured my ADSL-modem/router to act as a router. Now it works as it should but I can't get to my server using SSH,FTP,HTTP. It works in my LAN without a problem. Well, sometimes I can't connect to the WAN but that's rarely.

Now, when I try to connect from my school to my home server using PuTTY, it get's my IP-address and things in the upperbar but then says "Network error: Connection timeout".

I have blocked all traffic from WAN to LAN from my router and then made exceptions to this rule by allowing my SSH port,20,21,80 and 110 to by-pass the firewall. Then I use NAT to forward these to my server.

In server I've configured /etc/ssh/sshd_config to use my SSH port.
Also I have configured that it allows all services to be accessed from my router.

But, still I can't connect into it. Anything else to check?

If you have setup portforwarding to an internal statically assigned IP and have the needed server services running and there is no firewall on the server blocking then my guess is your provider is blocking common ports to stop users from setting up servers. Only way to check other than calling provider is set say the ssh port on the wan side to say port 2022. So the portforward will be your external IP plus port 2022 to internel IP port 22.

Brian1

grc.com now has a nice explanation of how to test for that possibility. I know it happens sometimes, but I think the rumor is more pervasive than the fact.

Is it possible that you are running a iptables? If so, try "iptables -L -n" and post it here. You may be blocking all incoming connections to your server w/ the firewall.

The cause might be in the iptables. If I recall, slackware installs iptables on default. I haven't delved into iptables yet at all. I'm only using the hosts.allow and hosts.deny files to control access to my system.

Interresting thing is that the connection to my server has worked. I don't recall where the error was back then. I might have been in the router firewall then.

I'll try to post the iptables info when I got to my server.