Some error messages in var/log/messages

Linux and Unix-Like SuSE
1

How are you?
SUSE V10 and 11.
In /var/log/messages I see these lines in some servers. I'd like to know what causes these errors and how to fix them.
Thank you,

error: PAM: Authentication failure for root from XXXXXXXX
Did not receive identification string from XXXXXXX
Invalid user suse-gm from XXXXXXX
pam_tally(sshd:auth): pam_get_uid; no such user
error: PAM: User not known to the underlying authentication module for illegal user suse-gm from XXXXXXX
Failed keyboard-interactive/pam for invalid user suse-gm from XXXXX port XXXXX ssh2
2

Easiest way is to move your ssh port. If you move the port, bots and other "things" will have difficulty finding your ssh.

If you don't need ssh, you can always just shut it down permanently (even uninstall it).

3

Can you trace where they are from, e.g. source IP address. Is it one of your company's or coming in externally? If it is external and you don't allow any external ssh or sftp etc. in, then you better speak with those that manage your company firewall.

If it's internal, then you have a local source to contact.

Robin