Question

Can't login to my server with my SSH key

I created a new droplet and set it to use the usual SSH key on my account that I generated a long time ago with PuttyGen on Windows. I’m on a Mac now so I just copied over the PPK file thinking that I could use it to login. Turns out I can’t. I tried changing the permission of the file using chmod 600 but that didnt work. I went back to my Windows machine and used PuttyGen to convert the .ppk to an open ssh one. Same filename but with a .pem extension. I still can’t login to my server. Im geetting this:

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    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 [a long string of letters and numbers]
Please contact your system administrator.
Add correct host key in /Users/me/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in /Users/me/.ssh/known_hosts:1
ECDSA host key for IPADDRESS has changed and you have requested strict checking.

Host key verification failed.

Anybody?

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Bobby Iliev
Site Moderator
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• April 18, 2020
Accepted Answer

Hi there @reyesjmf,

You could try using the ssh-keygen command to delete the invalid key from your known_hosts file. The command that you need to use would be:

  1. ssh-keygen -R "you server hostname or ip"

Let me know how it goes! Regards, Bobby

reyesjmf • April 18, 2020

@bobbyiliev It worked like a charm! I ran your command and tried to connect with:

$ ssh -i myKey.pem root@IPADDRESS

I got an error that my file wasn’t accessible and got “Warning: Permanently added ‘IPADDRESS’ (ECDSA) to the list of known hosts. Permission denied”

I tried again by adding the file path this way:

$ ssh -i ~/.ssh/myKey.pem root@IPADRESS

This time I was able to login.

Thanks for the help!