Re: UDP packet being blocked
From: Gerald Vogt (vogt_at_spamcop.net)
Date: Sat, 22 May 2004 19:19:10 GMT
> I notice on my firewall log that an outgoing UDP packet is frequently
> being blocked. The source IP address is my IP address 192.168.1.100 --
> router on a single computer -- and the destination address is
> 126.96.36.199, which is the IP address of my ISP, RoadRunner. The source
> port is 1137, the destination port is 53.
> I don't understand what this means. Why is an outgoing UDP packet
> going to my ISP and why is it being blocked? The system seems to be
> running OK.
Port 53 is DNS - Domain Name Service. It resolves the host names (e.g.
www.apple.com) to IP addresses (among other things). 188.8.131.52 is most
likely the configured DNS server for your connection (check with
"ipconfig /all" in a command prompt) Basically any connection to the
internet (except those, that use an IP address directly) requires the
DNS server. My NIS 2004 (compared to 2003 I think) does not have a
general DNS rule anymore but allows DNS only for configured application.
So I assume, that you have a program running that tries to access the
internet and that you block. Check the logs to find out which program it