Nameserver with Custom Hostname

Mark_Andrews at Mark_Andrews at
Wed Nov 10 19:26:02 UTC 1999

> Please help me understand the circumstances of a deadlock when A records time
> out if delegation NS names differ from those listed in domains.  I have a
> client with different NS names registered than listed in the domain, though
> the ip addresses of the NSs agree. I need a good technical arguement to
> encourage the domain owner to update the registrations, especially since it
> sounds like this is a problem.

	It all has to do with trust levels of different answers from 
	different sources.  Answers from the servers for the zone will not
	be replaced by those from the parent zone so when named goes back
	up the heirarchy to find missing glue it gets a referal from the
	parent zone back into the zone with a NS rrset which is not added
	added to the cache.  You then go looking for the A records again, 
	don't have them and repeat.

	The NS records in the parent zone are supposed to be the same as 
	the childs.  The only time when they should be different is when 
	you are changing servers.  In this case the parent should be a subset
	to the childs servers.

> Which names are used in cache? The version from root, or the version from the
> domain?
> Do non-auth servers ever query the domain for NSs?
> When an A RR ttl expires, does the non-auth NS query for the address of the N
> S
> name originally obtained from root (or a parent domain) or for the NSs listed
> from the domain?
> TIA,
> Bill Myers
> Total Network Solutions
> -----Original Message-----
> From: Mark_Andrews at [mailto:Mark_Andrews at]
> Sent: Monday, September 27, 1999 4:59 PM
> Cc: bind-users at
> Subject: Re: Nameserver with Custom Hostname
> > In article <gSgH3.19446$LL2.189348 at>,
> > konfused <dev at> wrote:
> > >I know of cases where one machine hosts various services including a
> > >name server, but the Hostname is unique and not NSx or DNSx.  However
> > >Internic believes the machine name is
> >
> > This means that the person who registered the domain submitted a different
> > name than what he put in his DNS zone files.
> >
> > >How is this accomplished?  Do the DNS records use NSx throughout the
> > >files and an A or CNAME for the friendly machine name?  Or is the other
> > >way around, and the records us the friendly name while an A or CNAME is
> > >used to map to NSx?
> >
> > Since this is not something you should do, I'm not going to give you
> > examples.  It's best to use the same name in the registration and the DNS
> > files.
> >
> 	It is essential that you use the same name, otherwise
> 	nameservers which rate answers on there source will deadlock
> 	if the A records time out.
> 	Mark
> --
> Mark Andrews, Internet Software Consortium
> 1 Seymour St., Dundas Valley, NSW 2117, Australia
> PHONE: +61 2 9871 4742                 INTERNET: marka at
Mark Andrews, Internet Engines Inc. / Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark_Andrews at

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