[CLUE-Tech] possible breakin attempt

[Mike]

Can anyone shed light on these messages in /var/log/auth.log:

(all on one line but will line wrap here)

Aug 30 12:46:50 mg2 sshd[10555]: reverse mapping checking getaddrinfo
for ip-202-147-54-103.asianetcom.net failed - POSSIBLE BREAKIN ATTEMPT!

There were 9 such messages on Aug 30th and 107 on Oct 9th.

What are they trying to exploit?

ckrootkit and rkhunter found nothing. What else I should check?

Thanks,

Mike