Question about recursive name resolution

[Mark_Andrews at isc.org]

> Hi,all
> 
> I'm just starting to learn the DNS. One question puzzles me that local or
> low-level name servers normally use recursive name resolution,but high level
> name servers closed to the root generally do not support it.Why? And if the
> high level name servers use recursive name resolution, can we expect much
> performance improvement? Thank you!
> 
> Jeffery

	Servers fall into three classes, authoritative, caching and both
	authoritative and caching.

	High level servers are generally dedicated to the authoritative
	role and hence don't need to offer recursion.

	Low level server are often performing both the authoritative and 
	caching roles hence they offer recursion to some (all) clients.

	Then there are servers which are only caching servers.
	
	Mark
--
Mark Andrews, Internet Software Consortium
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews at isc.org