This post is older than a year. Consider some information might not be accurate anymore.
Having multiple virtual machines for testing and POC (proof of concepts) you install for the “remote” access an OpenSSH server. Everytime you log in into a new machine, you might run into this legit warning:
tan@omega:~$ ssh tan@localhost -p 222
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ 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 a host key has just been changed.
The fingerprint for the ECDSA key sent by the remote host is
SHA256:MggEJZSCbAmRQXebLxzdtEt7qjJVdUcr+cv1CBl5OgY.
Please contact your system administrator.
Add correct host key in /home/tan/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /home/tan/.ssh/known_hosts:17
remove with:
ssh-keygen -f "/home/tan/.ssh/known_hosts" -R [localhost]:222
ECDSA host key for [localhost]:222 has changed and you have requested strict checking.
Host key verification failed.
Since there is already a host key for another virtual machine, you can disable the warning for localhost via config.
cat /home/tan/.ssh/config
Host localhost
NoHostAuthenticationForLocalhost yes
Otherwise you might end up removing the host key on every occasion.
