DNS queries with UDP and TCP

[Alejandro <alejandritox@ciudad.com.ar>]

Hi people, I have some low rate problems in my network and I think it
could be the DNS servers from my ISP I use in my proxy (squid) installed
in a Debian Sarge machine, they are open DNS's and they could have a big
traffic load.

But also I have read on the web that some common resolution queries to
DNS servers and their responses use TCP because they need a bigger
amount of bytes (I'm not talking about zone transfer, I'm talking about
of direct and reverse simple name resolutions). So do you think in my
firewall I have to open TCP/53 and UDP/53 ports in order to have name
resolution to my proxy, or just opening UDP/53 port is enough ???

Thanks a lot,


Alejandro