[comp.protocols.tcp-ip.domains] definition of sub-sub-domains

e07@nikhefh.nikhef.nl (Eric Wassenaar) (01/27/91)

Is it legal for a nameserver, authoritative for domain 'some.domain',
to define in its zone data file a sub-sub-domain (two levels deeper)
like
	foo.bar.some.domain	NS	somehost.some.domain

especially when 'bar.some.domain' is not defined, i.e. there exists
neither a SOA record, nor a NS record (nor any other record) for
'bar.some.domain' ?

I cannot find any information about this situation in the appropriate
RFCs. There exist many such cases in practice, and apparently it works,
but I am not sure if that is always guaranteed.
(Example: 'navo.navy.mil', 'nwc.navy.mil', etc., but no 'navy.mil')

Eric Wassenaar
-- 
Organization: NIKHEF-H, National Institute for Nuclear and High-Energy Physics
Address: Kruislaan 409, P.O. Box 41882, 1009 DB Amsterdam, the Netherlands
Phone: +31 20 592 0412, Home: +31 20 909449, Telefax: +31 20 592 5155
Internet: e07@nikhef.nl

gavron@alpha.sunquest.com (Ehud Gavron) (01/27/91)

In article <1131@nikhefh.nikhef.nl>, e07@nikhefh.nikhef.nl (Eric Wassenaar) 
writes...
# 
#Is it legal for a nameserver, authoritative for domain 'some.domain',
#to define in its zone data file a sub-sub-domain (two levels deeper)
#like
#	foo.bar.some.domain	NS	somehost.some.domain

	Yes, but add the trailing periods:
		foo.bar.some.domain.	ns	somehost.some.domain.

# 
#especially when 'bar.some.domain' is not defined, i.e. there exists
#neither a SOA record, nor a NS record (nor any other record) for
#'bar.some.domain' ?

	Yes.  Look at the nss records.  For example 
		boulder.co.nss.nsf.net.  
	
	There are no co.nss.nsf.net domains/hosts, yet the
	subsub of nss.nsf.net exists.

#I cannot find any information about this situation in the appropriate
#RFCs.

	RFC1035 does not prohibit this.  By its definition of
	<domain-name> and <label> the RFC definitionally allows
	it.  Obviously it works...

#but I am not sure if that is always guaranteed.

	What ever is? :-)	(not even the mb rr survived...)

#Eric Wassenaar
#-- 
#Internet: e07@nikhef.nl

	Ehud

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