Something with port 53

[Gannater János]

Hello,

I've posted this question to the freebsd-newbies list, but there nobody 
could answer it.
Please help me with this qestion...

I have a box with 2 IP addresses (with aliases).
I usually get these error messages:
Connection attempt to UDP IP_ADDR_1:1409 from IP_ADDR_2:53
What does this mean?
I don't have any DNS server installed on the computer and the firewall 
is disabled on the system as well.

etc/hosts:
::1                     localhost localhost.domain.com
127.0.0.1           localhost localhost.domain.com
IP_ADDR_1         www.domain.com www
IP_ADDR_2        mail.domain.com mail

etc/sysctl.conf
net.inet.udp.blackhole=1

Thank You.