Easy solution to“Warning! Remote Host Identification has changed!”

What to do when you connect a server using SSH for the first time you get to witness the below messages?

On Linux or Mac OS X computer

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ 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 RSA key sent by the remote host is

On Microsoft Windows, if using PuTTYcache

WARNING – POTENTIAL SECURITY BREACH!
The server’s host key does not match the one PuTTY has cached in the registry. This means that either the server administrator has changed the host key, or you have actually connected to another computer pretending to be the server.

Is this what worrying you?

Don’t worry! Know the reason first.

SSH aka Secure Socket Shell is the most widely used network protocol that you are using to manage the system and its various applications remotely. It is highly secured as it provides robust password verification and Public Key verification, and fully encrypted communication between the connected computers in an open network.
And such a message usually appears when the RSA Fingerprint has been changed on the remote server, but the client’s computer still holds the former RSA fingerprint.

So, it’s when you install a new OS template on the server, it is quite common to find such a warning message on your client’s computer screen.

How to fix this miss?

Fixing this issue will not take much of your time. You only need to follow the below-mentioned steps-

If using LINUX or Mac OS X Computer

Step 1: Trace the line where it is mentioned –
Offending RSA key in /path/.ssh/known_hosts:x
(Just remember the value of path and x will vary)
Step 2: Open the file in your preferred text editor
Step 3: Remove the entire text line where number x has been pointed
Step 4: Save the changes and exit the text editor
Step 5: Connect it to the server using SSH.

If using Microsoft Windows

You get three options when this warning message is displayed:

1. In case you have re-installed the OS or made any necessary configuration changes in the server, just click “Yes” for updating PuTTY’s cache in the server’s latest RSA fingerprint. Hopefully, such a message will not turn up when you connect to the server, again in future.

2. In case you are not aware of the server configuration, Click “No” and connect to the server without updating anything. But the next time when you connect again, this warning will appear again.

3. In case you are aware that no configuration changes have been made in the server then probably it’s a cyber-threat, where the attackers are trying to break the connection. So, don’t proceed, click “Cancel” and contact the web hosting provider immediately.

Are you finding this article helpful? Don’t forget to share your views with us. Thank you!