How to add a remote server into ssh gateway using SSH keys?

This article explains how to add a remote server to an SSH gateway using SSH keys, even when the root password is unknown.

When adding the target server to the SSH gateway, select 'keep server password' for password management, and manually add the SSH gateway's public key, which can be found in Servers -> Global key, to the /root/.ssh/authorized_keys file on the target server.

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