TCP domain connection

[Igor Mozetic <igor.mozetic@uni-mb.si>]

I'm observing TCP connections to port 53 (domain) to our
(secondary) name server from unknown locations.
ippl.log looks like:

Jun  3 21:51:59 domain connection attempt from  [x.x.x.x]
     (x.x.x.x:3302->y.y.y.y:53)

As far as I understand, these are not DNS queries since they
are UDP. Is this a break-in attemtp, should I ignore it, how
to prevent it (TCP wrappers don't work here) ... ?

-Igor Mozetic