Setup new Ubuntu server. Verified network settings working correctly. Verified the firewall is off. Can ssh locally and telnet locally to port 22.

Cannot telnet nor ssh from another machine.

Have tried everything including search the internet. I have unchecked the GSSAPI setting in Putty, but since you can't telnet to port 22 from a different computer, it seems something is blocking the connection or the Ubuntu server is blocking non-local connections.

  • Okay, I can use telnet to open a session to port 22 when from the local server and from another machine. It must have something to do with the connection settings for ssh. – Little Mitch Nov 11 '18 at 1:13

I reinstalled the OS. Fixed the problem.

I suspect that one of the packages that Ubuntu offered as "extras" that I previously installed must have been hijacking port 22 or something.

Anyway, I did not select any of the extras. Clean system works.

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