If a CSE Server is replaced - what to do

If a CSE server is replaced, it is possible the ssh keys are recreated and you will receive a "man in the middle" warning. SSH uses a secure mechanism involving keys. The key you have for the upgraded machine no longer lines up. If this is the case, you need to clear out that specific key. Never automatically do this. If you receive a warning, double check the CSE homepage to see if this is real or not. If there is nothing under announcements, do NOT clear it out. Instead contact manager@cse.

Windows SSH Client Solution:

In order to solve the problem on the windows ssh client, accept the new host key and overwrite the old.

Or under the Edit menu select the settings option. Then expand Server Authentication and select Host Keys. Delete the line for hostname, and then the next time you ssh, the new key will be saved.

Windows Putty Solution:

Putty is a little difficult with this. The key is stored in the registry. You need to clear the host entry under the registry tree: HKEY_CURRENT_USER\Software\SimonTatham\Putty

Unix SSH Client Solution:

In order to solve the error message being recieved about man in the middle, just remove any occurance of the hostname in your ~/.ssh/known_hosts and ~/.ssh/known_hosts2 files. The next time you login, the new key will be saved.