I'm trying to connect to an ssh sever running on cygwin on my home computer through putty on my laptop, this works fine both inside my network and outside on port 22 but on port 443 it times out. Which is a bit of a problem as the network I'm going to be connecting from prevents me from using 22. I assume its a port forwarding issue but I've set up a rule in my router setting (isp provided BT HomeHub 3 Type A) but it doesn't seem to have opened the port. Any ideas on how to solve the issue are greatly appreciated.

  • 1
    And is the server listening on port 443?
    – Jakuje
    Nov 19, 2015 at 19:45
  • Yes, sorry forgot to mention that I changed the sshd_config so it is Port 22 Port 443. I should get more sleep.
    – CMCK123
    Nov 19, 2015 at 19:49
  • 2
    Did you restart sshd server? Do you have the port open in firewall? Does sshd have access to this port through SELinux or other control mecahnisms? Too much question unanswered.
    – Jakuje
    Nov 19, 2015 at 19:51
  • Yes it's been restarted and the ports are open in the firewall, for your last question I'm not to sure how to check that.
    – CMCK123
    Nov 19, 2015 at 20:19
  • Check if something else is running on port 443 and pc firewall rule.
    – Diamond
    Nov 19, 2015 at 20:37

1 Answer 1


When you telnet (or nc) to a port that has an ssh server listening, you should obtain a string of characters, something like

SSH-2.0-OpenSSH_6.0p1 Debian-4+deb7u2

If you don't obtain a string like that, then you are not speaking to an ssh server, and if you try speaking ssh to it, then your client will time out.

If it doesn't work, change your server back to port 22 so that ssh works again, and check how it looks. Try from the server itself. Change to port 443 and try again from localhost. Once that is OK, try from outside your server. If it does work from localhost but not from the outside, your problem is either port redirection, filtering, or some other kind of firewall.

In the unlikely case where you get the OpenSSH string but the OpenSSH client still times out, your problem is different, and you'll need to provide the -vvv output from ssh. You might have an MTU problem.

Not the answer you're looking for? Browse other questions tagged or ask your own question.