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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

More posts in my blog ElBruno.com.

More info in https://beacons.ai/elbruno


References

My posts on Raspberry Pi ⚡🐲⚡

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

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

  1. I came about your post because I had the exact thing happening on my raspberry Pi but I only shut it down and turned it on the next day. No re-flashing or similar action.
    Even worse, I could not fix it, e.g. copy a new key the Pi closed connection every time I put in my password. Could not ssh into it – same thing closed connection on port 22. Truly puzzled what happened here. Now I re-flashed and I’ll set it up from scratch. Maybe you have some insight on what is happening here. I need to be able to work with this hardware without jumping through the hoops like this.
    Any tip is greatly appreciated.

    Like

  2. Thanks, it worked.

    Like

  3. mays alsayed Avatar
    mays alsayed

    you’re amazing, thanks a lot

    Like

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