Generally you can ignore these. If you're using iptables, you can use
swatch to add DROP entries to your INPUT chain -- this was discussed a
while back on this list. Or, you could look into using tcpwrappers with
sshd. A way to improve security is to not allow root logins through ssh.
To obtain root access, you'd login with your normal account and "sudo su
-". To change this default behavior to be more secure, edit
/etc/ssh/sshd_config and change:
#PermitRootLogin yes
to
PermitRootLogin no
Cheers,
rayc
NSK