Git says "Warning: Permanently added to the list of known hosts"

Question

Solution: create a ~/.ssh/config file and insert the line:

UserKnownHostsFile ~/.ssh/known_hosts

You will then see the message the next time you access Github, but after that you'll not see it anymore because the host is added to the known_hosts file. This fixes the issue, rather than just hiding the log message.

This problem was bugging me for quite some time. The problem occurs because the OpenSSH client compiled for Windows doesn't check the known_hosts file in ~/.ssh/known_hosts

ssh -vvvvvvvvvvvvvvvvvvv [email protected]

debug3: check_host_in_hostfile: filename /dev/null
debug3: check_host_in_hostfile: filename /etc/ssh/ssh_known_hosts
debug3: check_host_in_hostfile: filename /dev/null
debug3: check_host_in_hostfile: filename /etc/ssh/ssh_known_hosts
Warning: Permanently added 'github.com,207.97.227.239' (RSA) to the list of known hosts.

Add the following line to your ssh config file ($HOME/.ssh/config):

LogLevel=quiet

If running ssh from the command line add the following option to the command string:

-o LogLevel=quiet

For example, the following prints out the gcc version installed on machine.example.org (and no warning):

ssh -o UserKnownHostsFile=/dev/null \
    -o StrictHostKeyChecking=no \
    -o LogLevel=quiet \
    -i identity_file \
    machine.example.org \
    gcc -dumpversion

Set LogLevel to ERROR (not QUIET) in ~/.ssh/config file to avoid seeing these errors:

Host *
   StrictHostKeyChecking no
   UserKnownHostsFile /dev/null
   LogLevel ERROR

That message is from SSH, which is warning you that you are connecting to a host which you've never connected to before. I wouldn't recommend turning it off, since it would mean that you might miss a warning about a host key changing, which can indicate a MITM attack on your SSH session.

To suppress warning messages for ssh you can add the following lines to ~/.ssh/config:

Host *
LogLevel error

That will disable warnings but not error messages. Like the other settings in ~/.ssh/config you can configure the LogLevel on a per-host basis if you want a more finegrained control.

It mainly means there are changes for the key for that host ~/.ssh/known_hosts, and it will not automatically UPDATE it. Therefore every time you get this warning message.

This happens often for the connecting to the re-created virtual machines, which changes the key with the same IP address

Solution

If you only have one entry, then you can delete the ~/.ssh/known_hosts file, and after first connection, that the key will be there, and no warning messages after that.

If you have multiple entries, then you can use command below to remove

$ ssh-keygen -R <hostname>

It works fine for me

add your private key to the ssh-agent with:

ssh-add ~/.ssh/id_rsa