If you encounter the error Permission denied (publickey) when you try to connect to your GitHub Enterprise instance via SSH, you will need to make sure you are connecting over port 122, and you may need to explicitly specify which private SSH key to use.

Using a command-line option

Run ssh with the -i argument as follows:

ssh -i /path/to/ghe_private_key -p 122 admin@hostname

Using an SSH config file

Add the following lines to your SSH config (~/.ssh/config):

Host hostname
  IdentityFile /path/to/ghe_private_key
  User admin