So you have a extensive IBM AIX environment with all of your SSH keys set-up, but now you have built a number of Linux servers which you want to add into this key range. So you copy over the existing authorized_keys file from your AIX system to a Linux host, then go to log in and find that nothing has changed; the ssh session still prompts you for the root password:
[aix1:root] /root # ssh rh1
Last login: Mon Nov 4 13:48:44 2013 from aix1.domain.com
So why is it not working? Simply their could be a number of default settings for SSH that would be stopping your systems from authorizing correctly, so if you go through this list you should find at the end of it one of them will resolve your issue. This example is taken from my own system where the last command fixed the issue:
[root@rh1 ~]# chown -R root:root ~/.ssh
[root@rh1 ~]# chmod 700 ~/.ssh
[root@rh1 ~]# chmod 500 ~/.ssh/*
[root@rh1 ~]# restorecon -R -v ~/.ssh
restorecon reset /root/.ssh context unconfined_u:object_r:admin_home_t:s0->unconfined_u:object_r:ssh_home_t:s0
restorecon reset /root/.ssh/authorized_keys2 context unconfined_u:object_r:admin_home_t:s0->unconfined_u:object_r:ssh_home_t:s0
restorecon reset /root/.ssh/known_hosts context unconfined_u:object_r:admin_home_t:s0->unconfined_u:object_r:ssh_home_t:s0
As mentioned after running this I was able to SSH to the systems as per all of my AIX clients.
Note: restorecon program.
This program is primarily used to reset the security context (type) (extended attributes) on one or more files.
It can be run at any time to correct errors, to add support for new policy, or with the -n option it can just check whether the file contexts are all as you expect.