#RaspberryPi – How to solve the SSH warning: WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!

Buy Me A Coffee

Hi !

When you test and play around with your Raspberry Pi, you may need to format again your Raspbian SD Card, and then start everything from scratch. This is a trivial process, and is usual to setup the device to connect automatically to a Wifi network and also enable SSH (I wrote about this, see references).

And then, when you try to connect via SSH you may get this warning

 C:\Users\bruno> ssh pi@192.168.1.247
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    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: Not here ! 
Please contact your system administrator.
Add correct host key in C:\\Users\\bruno/.ssh/known_hosts to get rid of this message.
Offending ECDSA key in C:\\Users\\bruno/.ssh/known_hosts:10
ECDSA host key for 192.168.1.247 has changed and you have requested strict checking.
Host key verification failed.

This is a very common scenario, and because I forgot how to fix it, I’ll write the simple command remove all keys belonging to the IP / hostname from the known_hosts file.

# ssh-keygen -R <host>
ssh-keygen -R 192.168.1.247

And that’s it, keys removed and now I can connect via SSH

Happy coding!

Greetings

El Bruno

References

My posts on Raspberry Pi

Dev posts for Raspberry Pi
Tools and Apps for Raspberry Pi
Setup the device
Hardware