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From: del@algol.mlb.semi.harris.com (Don Lewis)
Newsgroups: comp.protocols.tcp-ip.domains
Subject: Re: Removing unneeded glue records
Message-ID: <1991Feb8.003137.25387@mlb.semi.harris.com>
Date: 8 Feb 91 00:31:37 GMT
References: <1991Feb3.225247.14168@ugle.unit.no> <1991Feb5.064846.5711@mlb.semi.harris.com> <1991Feb6.185422.8886@ugle.unit.no>
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In article <1991Feb6.185422.8886@ugle.unit.no> he@idt.unit.no (Havard Eidnes) writes:
>In article <1991Feb5.064846.5711@mlb.semi.harris.com>, del@algol.mlb.semi.harris.com (Don Lewis) writes:
>|> I made a similar change a while ago.  My patch is a bit fancier
>|> (and much more complicated).  It has the advantage that it only includes
>|> the extra A records if they reside below an NS RR delegating authority
>|> to a subzone.
>
>I think my fix also does that, because doaxfr is called recursively for all
>RRs in a zone (or did I read the code wrong?). Anyway, it appears to
>exhibit this desireable behaviour with my fix.

Your fix only includes the A records if they only if they reside below the
NS.  It does not include the A records if they reside below another NS
in the same zone.  Example zone file for foo.com.

; Stock BIND and your version will include the A RR for hosta in the zone xfer
; (redundant)
		IN	NS	hosta
; Stock BIND may include the A RR for xyzzy.edu
		IN	NS	xyzzy.edu
; All versions include the A RR hosta
hosta		IN	A	x.x.x.x

; All versions include the A RR for host1.sub1
sub1		IN	NS	host1.sub1
; Stock BIND and my version include the A RR for host3.sub2 (required glue)
		IN	NS	host3.sub2
; Outside the zone, not included in the zone xfer
host1.sub1	IN	A	x.x.x.x
; Outside the zone, not included in the zone xfer
host3.sub2	IN	A	x.x.x.x

; Stock BIND and my version include the A RR for hosta (redundant)
sub2		IN	NS	hosta
; Stock BIND and my version include the A RR for host1.sub1 (redundant)
sub1		IN	NS	host1.sub1
; All versions include the A RR for host2.sub2
		IN	NS	host2.sub2
; Outside the zone, not included in the zone xfer
host2.sub2	IN	A	x.x.x.x

The main problem with your version is that it does not transfer the
A RR for host3.sub2.  The only real defect in my version of the fix
is the inclusion of a few redundant A RRs.

Also, if the a host acts as server for both foo.com and sub1.foo.com,
and there is an MX (or other such RR) for sub1.foo.com (which is
part of the sub1.foo.com zone), stock BIND includes this RR in zone
transfers of the foo.com zone.  My patch takes care of this problem as
well.
--
Don "Truck" Lewis                      Harris Semiconductor
Internet:  del@mlb.semi.harris.com     PO Box 883   MS 62A-028
Phone:     (407) 729-5205              Melbourne, FL  32901