[dns-operations] ANY request

Mark Andrews marka at isc.org
Mon Feb 8 00:54:26 UTC 2010

In message <20100207203735.GA31626 at sources.org>, Stephane Bortzmeyer writes:
> On Sun, Feb 07, 2010 at 10:40:48AM +0100,
>  Phil Regnauld <regnauld at nsrc.org> wrote 
>  a message of 71 lines which said:
> >       Also, answers to ANY are somewhat implementation dependent,
> For a cache, yes, it is a well-known issue. But for an authoritative
> name server? I cannot find anything in the RFC but I always assumed
> that ANY, for such a name server, meant "send *all* the records for
> this QNAME and, if you cannot, set the TC bit". Was I wrong?

RFC 1035, 4.2.1. UDP usage

Messages carried by UDP are restricted to 512 bytes (not counting the IP
or UDP headers).  Longer messages are truncated and the TC bit is set in
the header.

RFC 1035, 3.2.3. QTYPE values

*               255 A request for all records

Putting the two together you should have TC set.
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: marka at isc.org

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