Path: utzoo!attcan!uunet!maverick.ksu.ksu.edu!ux1.cso.uiuc.edu!mp.cs.niu.edu!rickert
From: rickert@mp.cs.niu.edu (Neil Rickert)
Newsgroups: comp.protocols.tcp-ip.domains
Subject: Re: DNS glue records and BIND 4.8
Message-ID: <1990Sep25.140536.16449@mp.cs.niu.edu>
Date: 25 Sep 90 14:05:36 GMT
References: <1918@ccadfa.adfa.oz.au>
Organization: Northern Illinois University
Lines: 48

In article <1918@ccadfa.adfa.oz.au> cjsv@ccadfa.adfa.oz.au (Christopher JS Vance) writes:
>The question I have is in regard to the specification of glue records
>for servers outside my domains which perform secondary service for me -
>each of my domains (except 127, of course) has the same list of
>secondary servers. 
>
>When the same host is listed as a foreign secondary server in each of my
>domains, are the glue A records:
>

 While I admit to being a non-expert, and possible mistaken on this - and
doubtless I will be corrected in this case - I suspect you don't need any
glue records at all.

 As I understand it, the only time you need glue records is when you have
an NS record for a subdomain of yours and are not yourself a name server
for that subdomain.  Under any other circumstances the needed A-record
can be found by the usual search methods starting at the root servers.

 If, for example you are the primary name server for BAR.EDU, and the there is
to be a subdomain  FOO.BAR.EDU, with SOA at HOST.FOO.BAR.EDU, then the official
source about HOST.FOO.BAR.EDU, including its A-record, must be found from from
HOST.FOO.BAR.EDU.  This is a vicious circle, and is the case where a glue
record is needed.  The easiest way to provide the glue record is for you to
be a secondary server for FOO.BAR.EDU, which is often the case.  If the
name server for FOO.BAR.EDU is in BAR.FOO.COM no glue record is needed for
the usual search paths should get an A-record for BAR.FOO.COM.  Actually it
is my impression that in this case your nameserver probably does this search and
keeps the A-record on hand anyway.

 It is better to not have a glue record unless absolutely necessary, for
otherwise this is another record which must be kept up to date, yet for
which you are technically not responsible.

 The conclusion is that wherever you delegate a subdomain, you should
probably be a primary or secondary server yourself, in which case you need
no glue record - it is already there.  You should never need glue records
for reverse mappings.  The main need for glue records is for the root servers
which handle so many subdomains they cannot possibly be secondary servers for
most of them.

 Hope this helps.   And if I am confused I hope someone corrects me.

-- 
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  Neil W. Rickert, Computer Science               <rickert@cs.niu.edu>
  Northern Illinois Univ.
  DeKalb, IL 60115.                                  +1-815-753-6940