SSH - logging in remotely - 'to' secure? ;)

[Bobby]

Hi all,

Anyone here got any experience with SSH? Trying to set it up so I can connect to a Linux server remotely, but without any luck. Am port forwarding port 23 on the router to the linux server ... but not working and am a bit stuck for ideas.

Can any networking experts here lend a hand? Thanks!

[Paul Adams]

Isn't SSH traditionally TCP port 22, and Telnet is port 23?

[Bobby]

Yep, you're right - I did mean 22, I have forwarded them both, though, just to be sure.

[herulach]

By not working what exactly do you mean? First thing id check is whether the port forwarding is breaking it, can you connect to it from a machine on the same lan? If so then its something with your router. If thats the case then one solution is to put it in the dmz, but its not something id relish doing. You could also try a port scanner to see if its actually open. You havent got some kind of iptables thing going have you? COs it could be set to auto reject ports you havent explicitly open on the linux machine, IIRC they arent all open by default like on a windows box.

[Bobby]

I can connect find from any machine in the local lan - which as you say points to a problem with the router. However, I forwarded port 80 and started up Apache and can see a test page fine externally. So ... something to do with SSH specifically? Strange one, this ...

[herulach]

Hmm, curious, what ISP are you using? Some of them will block a lot of ports. try setting sshd to listen on port 80 and see if you can connect then.

[Bobby]

Good thinking - I'll give that a try.

[Bobby]

Right - have set SSH server on port 80. Tried to connect, and got an entry logged by the firewall, which was further than it was getting before. Set firewall to allow access to that IP, but still failed to connect. Interestingly, the IP address in the firewall log is different from that of the machine I'm trying to connect from. Could this be an intervening proxy server somewhere? If so, any ideas on how I can get around it?

[ikonia]

ok - return to basics, take ssh off the webserver port and put it back to the orgional / default configuration.

Now lets get some basic problem debugging ssh to your linux server with a -v flag

ssh -v $your_user@$remotehost

and lets see what the output is

Also - if you share the IP address/hostname someone/me can try ssh'ing to it just to check connectivity.

Lets get the basics right before going into "custom" configurations.

[MiggyMan]

Are you trying to connect to the inside, from the inside, via the outside address.

[Bobby]

Getting 'Connection timed out' message with the verbose switch.

MiggyMan - am connecting to the IP address assigned by my ISP, on a port forwarded to the Linux server machine (with a IP address from the reserved range), from an external location.

Hmmm ...

[ikonia]

time out means either ssh is not running on the server your connecting to, or the traffic is not getting there.

I'd be its the port forward not working. Chuck us the ip address and I'll run a test and see whats what, just to remove the obvious.

[mjhants]

Must be the port forwarding. Whats the router being used?
Or guess it could be IPtables config if setup on the Linux box.

[ikonia]

done further testing on this, problem appears to be at the client end