According to this reported BUG 1405158 some Linux versions will not accept multiple authorized key files. This is a problem as I am connecting to a server with a non-root user. If I add that user key to the main authorized_keys file in /root/.ssh permission is denied for that user, as you would expect.
Is there any quick way around this. The suggestion at the bottom of the bug report to add a root application for this purpose is rather painful.
So I just want to be able to login to the user folder from another server using key authentication, this should be easy, and I have it working fine on other versions already.
There is no "main authorized_keys file in /root/.ssh". It is just the authorized_keys file for the user "root".
If you log in with the name "user", than you have to place the key in the directory ~user/.ssh . Why would you need to specify multiple files?