Breakin attempt in the log

[User Gandalf]

 Hello,

I have thousands of similar lines in my security log each day:


Jun  9 06:34:12 designaproduct sshd[58759]: reverse mapping checking getaddrinfo for ev1s-67-15-10-78.ev1servers.net failed - POSSIBLE BREAKIN ATTEMPT!

Is this something I need to fear of?

Thanks,

   Laszlo