Useful comment about git using the ECDSA key instead and running into a mismatch issue (from the Github discussion):
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After I followed the instructions to remove the old RSA key, `git pull` started using the ECDSA key, and now shows this warning:
Warning: the ECDSA host key for 'github.com' differs from the key for the IP address '20.205.243.166'
Offending key for IP in /home/forge/.ssh/known_hosts:87
Matching host key in /home/forge/.ssh/known_hosts:88
Are you sure you want to continue connecting (yes/no)?
In this case, I think the old ECDSA key for the github.com IP needs to be removed from `known_hosts`. This can be done with:
The ECDSA key hasn't changed. As pointed out elsewhere in this thread, the official command `ssh-keygen -R github.com` is incomplete -- it doesn't remove IP address entries, they need to be removed manually. What you got was a conflict between the ECDSA key and the old RSA key left over in ~/.ssh/known_hosts (the error message was unclear).
Since GitHub's IP address is not stable, I suggest disabling the IP-checking feature using
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After I followed the instructions to remove the old RSA key, `git pull` started using the ECDSA key, and now shows this warning:
In this case, I think the old ECDSA key for the github.com IP needs to be removed from `known_hosts`. This can be done with: It worked for me, hope this helps.I'm not sure why the ECDSA key of the github.com IP has supposedly changed - maybe someone can clarify this?