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From: jcurran@SH.CS.NET (John Curran)
Newsgroups: comp.protocols.tcp-ip.domains
Subject: Re: nameserver for part of a zone ?
Message-ID: <9104190350.AA04401@ucbvax.Berkeley.EDU>
Date: 18 Apr 91 14:37:02 GMT
References: <1991Apr17.114129.27761@odin.diku.dk>
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: inet
Organization: The Internet
Lines: 43

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> I would like to set up a BIND-server on a SCO-UNIX system, that has
> authority over a part of a zone, like this:
> 
> [1] All queries, outside the zone, are resolved as usual.
> [2] Queries inside the zone are tried against local (authoritative) data.
    > (Here in the file "myfile").
    > If the answer is found, it is returned, else [3] is tried.
> [3] The queries are recursively forwarded to other servers for the same zone.

> I even tried using both lines (with or without v.x.y.z), but no matter
> what I do, I have only [2] xor [3], can't I have both ? Maybe this is 
> gross, but it seems to me to be usefull gross, because "mydom.mytop" is
> shared between several organizations, who don't need to know most of
> the local names, I'd like to use.

Yes, it would be useful.  The problem is that BIND presumes that a domain
has a single authoritative server, and as such, once an authoritative server
has been asked, it will not ask another (if if the first request returned
"no data"). There is no manner for a server to return an answer of "unknown".

The most common method for handling multiple data sources is to delegate 
each into a seperate subdomain:
 
   Under FOO.COM
	Unit #1 gets SALES.FOO.COM
	Unit #2 gets ADMIN.FOO.COM
	etc..
 
This subdomains are delegated by placing NS records in the master zone file:
	
(In file for zone FOO.COM)
@	IN	SOA	...   
	IN	NS	myns.foo.com.
	IN	NS	myns2.foo.com.
	...
SALES	IN	NS	salesns.foo.com.
ADMIN	IN	NS	adminns.foo.com.

This allows each unit to administer their own records within the overall
domain.  You should also define secondary servers for these subdomains.
 
/John