Hallo 
 
Alejandro G. Belluscio <[EMAIL PROTECTED]> schrieb:

> Hello David,
> Wednesday, February 19, 2003, 11:29:47 AM, you wrote:
> David> DNS sometimes also uses TCP on port 53 for large packets, so you
> David> probably want to allow that as well.
> I don't think so. DNS uses TCP only for zone transfers.

Are you sure about that?  In RFC 1035 you can read:
-----8<-----
The Internet supports name server access using TCP [RFC-793] on server
port 53 (decimal) as well as datagram access using UDP [RFC-768] on UDP
port 53 (decimal).
----->8-----

Packets longer then 512 Byte can be truncated or the client ask over
TCP, is well explained in:
 "W. Richard Stevens - TCP/IP Illustrated, Volume 1: The Protocols"

I know, that the most of "normal" tcp-trafic ist transported by UDP, and
TCP is left for the zone transfers.

I also have block 53/tcp on my packetfilter, but just to be exact, DNS
also works over TCP.

> 2) No software has the security track record of BIND (ok, may be MS,

The 2 versions of bind that I have seen in OpenBSD aren't that bad.  But
for the version we have nerver seen in OpenBSD thats true.


best regards Maik

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