[enum-wg] more enum resolver confusion
Jim Reid jim at rfc1035.com
Fri Apr 1 16:36:05 CEST 2011
On 1 Apr 2011, at 15:08, Peter Andreev wrote: >> Once upon a time ENUM people mumbled about a resolver: something >> that sat in >> between the DNS lookup code and the application and did all the >> NAPTR record >> processing: order/preference issues, NTNs, service selectors, etc. >> This >> badly named beast would be the thing that dealt with any collisions >> and made >> sure the application only got to see the NAPTRs it cared about. > > Hmm, I thought ENUM resolver is just the same as ordinary DNS > caching server. > What the main difference between them? I hoped that had been clearly explained in the paragraph above. Obviously not. Oh well... The (hypothetical?) ENUM resolver would be some code that spoke to a stub resolver that made DNS lookups and had an API to whatever applications wanted to avoid doing NAPTR record processing for themselves. It was/is exceptionally stupid to call this middleware thing a resolver. Because it isn't one. That unfortunate choice of terminology creates needless confusion with DNS resolution. Sigh. This so-called "resolver" is actually a NAPTR record processor/filter that sits *above* some DNS API but *below* the application. This bit of middleware does not get involved in DNS resolution, apart from maybe making more NAPTR lookups if it has to go chasing a chain of NTNs. It does not disrupt or interfere with the usual DNS model of stub resolvers talking to resolving (cacheing) name servers talking to authoritative name servers.
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