Remedying a warning about an ECDSA host key

25th August 2024

During some website maintenance that I have been doing using my iMac, I encountered a message like the following at one point:

Warning: the ECDSA host key for '<server name>' differs from the key for the IP address '<server IP address>'

The cause was a rebuild of one of my web servers and changes to SSH keys that it caused. The solution in my case was to issue a command like the following:

ssh-keygen -R <server IP address>

That felt neater than editing ~/.ssh/known_hosts to remove the affected key. If the command does not remedy things for you, then editing the file should help. That, after all, is what the rest of the warning message suggested to me. My qualms about messing with files made me go with the command, and that got things sorted. There had been some use of ssh-copy-id too, which might be information that is worth having to hand.

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Remedying a warning about an ECDSA host key

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