Can someone please explain the following log to me. I'm new and would like to understand the basic process of what is exactly occuring.


Aug 6 03:22:58 nestle sshdu[26359]: log: Connection from
213.233.104.142 port 1479
Aug 6 03:22:59 nestle sshdu[26359]: log: reverse mapping
checking gethostbyname for 75dial253.xnet.ro failed -
POSSIBLE BREAKIN ATTEMPT!
Aug 6 03:23:16 nestle sshdu[26359]: log: Password
authentication for root failed.
Aug 6 03:23:16 nestle sshdu[26359]: log: Closing
connection to 213.233.104.142

Thanks,

4j9er

Somebody is trying to connect from IP 213.233.104.142 from port 1479 on that box.
Your sshd does a lookup of the IP address (213.233.104.142), gets the name address 75dial253.xnet.ro,
then uses the library call gethostbyname to see if it gets the orig number IP (213.233.104.142),
back again.
It dosn't get the same num back, so it concludes it's a possible break-in attempt, and refuses the connection.
Any legit box should resolve it's IP num eg 1.2.3.4 to a name address eg box1.some.where.ctry,
then if you run gethostbyname on box1.some.where.ctry, you should get 1.2.3.4 returned.

if you go to RIPE Whois you get:

domain-name: xnet.ro
description: MobiFon S.A. - Connex GSM
description: 3, Nerva Traian Street
description: Complex M101, Sector 3
description: Bucharest, Romania

etc....

HTH

If you filter ssh access down to only known clients, then you can prevent a lot of unwanted activity.

Thanks for the help.

4j9er