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Date: Fri, 28 Jun 1996 09:51:23 -0500
From: Alex Nash <alex@fa.tdktca.com>
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To: Ollivier Robert <roberto@keltia.freenix.fr>
CC: nate@mt.sri.com, current@FreeBSD.ORG
Subject: Re: IPFW bugs? (fwd)
References: <199606281414.QAA25287@keltia.freenix.fr>
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Ollivier Robert wrote:
> 
> It seems that Alex Nash said:
> > I believe DNS/tcp is for zone transfers only.  DNS/udp is all you need
> > for standard lookups.
> 
> Not really. If named see  that the answer will  be more  than 512 bytes  in
> size, it will send the answer with the TF  (truncated flag) bit set and the
> resolver is supposed to re-try the query with TCP.

Does our named do this?  I (briefly) went looking for this behavior and
found:

	if (hp->tc) {
		count -= arcount;	/* truncation had to affect this */
		if (!arcount) {
			count -= aucount;	/* guess it got this too */
		}
		if (!(arcount || aucount)) {
			count -= ancount;	/* things are pretty grim */
		}
		/* XXX - should retry this query with TCP */
	}

Alex