SSH memo

X11 forwarding on. (X program said ``Can not open display''.)

Situation: When you slogined machine, but can not run X11 program, please add -X to slogin or ssh.

Details: For a security reason, new environment usually disables the X11 protocol forwarding in default. You should enable this explicitly.

Note: Some cygwin environment does not fully trust the X auth connection. In such case, your X connection looks like to be cut out in short period. If you know the host can be trusted, you can use -Y option. But use with care.

Port forwarding


Solution: Use port forwarding function of ssh. ssh's `-L' option can forward a port on a local host to the given host and port on the remote machine.

Example 1: vnc connection : There are machines: local, firewall, and remote. The remote side, you run `vncserver' and want to connect from local through the firewall.

Example 2: scp :

Too slow ssh login


Suggestion: Check the GSSAPIAuthentication status with 'ssh -v'.

Solution: Please check the ssh_config manual page and understand the situation. If it is OK to not use GSSAPIAuthentication, you can add the folloing line in your ssh's configfile. (~/.ssh/config)

    GSSAPIAuthentication no

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