Why not alllow by default (auto installation mdoe) port 53 to be used for DNS exchange in UDP mode for known application?
All is in the title! :THNK
I.E. for applications like : Messenger Live, IE 7, …
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Port 53 is usually used by the Domain Names Service (DNS). DNS is a critical component of the internet, as it allows for an automatic translation of human readable names (like www.dshield.org) into internet addresses (123.32.123.32). In other words, DNS fulfills the same function as a directory assistance for the phone system.