Mostrar código-fonte de Removing a key from the Known Hosts file

Example: Sometimes you want to connect to a machine using the same address as a decommissioned one. And guess what? The keys have been decommisioned as well. If you try to SSH into the machine, you'll be prevented with an error such as this:

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@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
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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 RSA key sent by the remote host is
XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX:XX.
Please contact your system administrator.
Add correct host key in /home/user/.ssh/known_hosts to get rid of this message.
Offending RSA key in /home/user/.ssh/known_hosts:3
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This means that key number 3 in your known_hosts file is the offending key and has to be removed.

This is the right way to remove a key from your Known Hosts file (usually ~/.ssh/known_hosts):

<syntaxhighlight lang="bash">ssh-keygen -f ~/.ssh/known_hosts -R machine.address</syntaxhighlight>

You may need to repeat the command using the IP address instead of a network name.