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Re: UDP packet/DNS server

  • From: Megatron
  • Date: Mon Sep 28 16:04:51 1998


On Sun, 27 Sep 1998, Matthew Petach wrote:

> > 
> > Hello Nanog,
> > 
> > I am trying get zone trasfer from a host, but it seems that because of
> > firewals?, I can not get any record.
> > They acknowelged that there is a host behind the firewalls but they claim
> > it should not affect it. (I don't believe it.) 
> > But I don't know how to check/prove that  if certain host can
> > receive/send an UDP packet.
> 
> Zone transfers are handled via TCP, not UDP.  See if you
> can telnet to port 51 on their nameserver; if you can't
> get a connection established,  you won't be able to do
> a zone transfer.
>  
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.

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

Cheers

> > TIA,
> > Tatsuya
> 
> Matt
> 






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