UDP packet/DNS server

I think you mean port 53. This is both TCP and UDP. I thought DNS
used both TCP and UDP. Thus firewall that is blocking UDP traffic will
cause zone updates to fail.

You're right, my mistake. Sorry! :frowning:

name 42/udp nameserver
whois 43/tcp nicname # usually to sri-nic
domain 53/tcp
domain 53/udp