Strange messages in mail queue

[User Gandalf]

Hello,

I might be offtopic...
I always get a long daily output from periodic.


Mail in local queue:
-Queue ID- --Size-- ----Arrival Time---- -Sender/Recipient-------
1D3C91DD4AA    45937 Tue May 23 10:54:42  MAILER-DAEMON
            (connect to onmail02.ongov.net[12.33.98.207]: Operation timed out)
                                         robinrandall at ongov.net
571EC1DD443    28752 Thu May 25 00:40:30  MAILER-DAEMON
                 (connect to paramed.biz[204.251.15.174]: Operation timed out)
                                         nicholas at paramed.biz
C04121DD4A0    28736 Mon May 22 13:20:50  MAILER-DAEMON
            (connect to pistonheads.biz[195.225.218.139]: Operation timed out)
                                         philip at pistonheads.biz

and many others. Is this a breakin attempt? Or is this normal? I do not know any of the e-mail addresses. 

Thanks,

   Laszlo