DNS requests switch from UDP to TCP

Date: 04/18/05

Date: 18 Apr 2005 06:12:04 -0700

Hello everybody,

I have witnessed a strange behavior of my machine and would like
to understand what has been happening. The situation is as follows.
My machine, which is online 24/7, uses fwlogwatch to generate daily
reports about connection attempts. I use a switch that makes
fwlogwatch try to resolve IP addresses, so that it sends requests
to an exterior DNS server when preparing a report. Usually, these
requests use UDP. Still, I have seen several times it using TCP
for these queries. My question is: What can make a program use TCP
for DNS requests?