I have set up ssh key pairs between my desktop and two servers, and from the servers to my desktop, but after reinstalling the OS on my desktop, I can't re-establish the key-pair going into my desktop by this:
mkdir ~/.ssh
chmod 700 ~/.ssh
ssh-keygen -t
ssh-copy-id username@server
I get the following error:
(names in italics changed to protect the innocent My desktop is Ubuntu, and I can't find the answer here)
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @ @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY! Someone could be eavesdropping on you right now (man-in-the-middle attack)! It is also possible that the RSA host key has just been changed. The fingerprint for the RSA key sent by the remote host is ab:cd:ef:gh Please contact your system administrator. Add correct host key in /home/user/.ssh/known_hosts to get rid of this message. Offending key in /home/user/.ssh/known_hosts:1 RSA host key for user.server has changed and you have requested strict checking. Host key verification failed.
The problem occurs if the host key has expired or been altered (for example, a new install on the server side), so it no longer matches the key in your known_hosts
You can delete the key(s) currently associated with the host and attempt to SSH once more. This ensures both the client and server recognize the new key.
ssh-keygen -R hostname
This deletes the offending key from the known_hosts
The man page entry reads:
-R hostnameRemoves all keys belonging to hostname from a known_hosts file. This option is useful to delete hashed hosts (see the -H option above).