~/.ssh/known hosts

ssh-keygen -R SERVER_NAME        -R Removes all keys belonging to hostname from a known_hosts file

ssh-keyscan github.com >> ~/.ssh/known_hosts

See also

• ssh-keyscan
• ssh-keygen [ -R, -t | -p | -i | -y | -f | ~/.ssh/id_rsa | --help ] ~/.ssh/known_hosts
• OpenSSH: ssh, ssh -O, -i, -t, -T, -N, -V, /etc/ssh/ssh_config, ssh --help