[56040] in North American Network Operators' Group
Re: [Re: [Re: M$SQL cleanup incentives]]
daemon@ATHENA.MIT.EDU (Doug Barton)
Fri Feb 21 23:25:07 2003
Date: Fri, 21 Feb 2003 20:24:31 -0800 (PST)
From: Doug Barton <DougB@DougBarton.net>
To: "E.B. Dreger" <eddy+public+spam@noc.everquick.net>
Cc: nanog@merit.edu
In-Reply-To: <Pine.LNX.4.44.0302220157380.30478-100000@www.everquick.net>
Errors-To: owner-nanog-outgoing@merit.edu
On Sat, 22 Feb 2003, E.B. Dreger wrote:
> BB> Recent versions of un*x BIND will pick a random port above
> BB> 1024 for udp conversations. It can and has picked 1434.
>
> Standard socket(2) behavior. BIND [hopefully] runs chown(2)ed,
> so the source port number must be >= 1024.
At startup, named bind(2)'s a UDP port to send queries from, and get the
answers back on. In the absence of a query-source option that specifies
otherwise, this will be a random ephemeral port, however that's defined on
the system. TCP queries follow "standard" behavior, binding a random
ephemeral port for each query.
Pardon the pedantry, but since this is an often misundertood topic, I
thought it might help to lay out the facts.
HTH,
Doug
--
"The last time France wanted more evidence, it rolled right
through Paris with a German flag." - David Letterman
