On 2/14/2010 6:10 PM, Rob Austein wrote: > At Sun, 14 Feb 2010 18:02:48 -0600, Laurence F Sheldon, Jr wrote: >> >> I thought I understood but from recent contexts here it is clear that I >> do not. >> >> I thought a resolver was code in your local machine that provide >> hostname (FQDN?), given address; or address, given host name (with >> assists to build FQDN). >> >> And I thought a "server" was a separate program, might be on the same >> machine, might be on another machine (might be on the local net, might >> be distant) that the resolver code called for information that was not >> in local cache. >> >> Just what is the straight scoop? > > No doubt Olafur will beat me up yet again for not having written the > DNS lexicon years ago, but: > > - A "resolver" is something that implements the "resolver" (ie, > client) role in the DNS protocol. It might be a stub resolver, the > client side of a recursive nameserver, a pure iterative resolver, > .... > > The defining characteristic is that it send queries (QR=0) and > receives responses (QR=1). > > - A "name sever" is something that implements the "nameserver" (ie, > server) role in the DNS protocol. It might be an authoritative > nameserver, the server side of a recursive nameserver, .... > > The defining characteristic is that it receives queries (QR=0) and > sends responses (QR=1). > > Clear enough?
Yes--tracks with what I thought, pretty much--I was missing the clientness of the resolver code to go with the serverness of the server. > Mapping protocol definitions onto the plethora of terms used by > operators in the field is left as an exercise for the reader, no > sarcasm intended. DNS is an old protocol, there are an awful lot of > people who think they understand it, I am one of those is sure he understands it--which belief crumbles when I try to explain it to somebody else. and each of those people has > their own set of terms that they're comfortable using. The > definitions above are what I rammed through the IETF during several > rounds of standards writing, but I would be the first to admit that > not everybody uses the terms the same way as I do. DNS arcana is one of the things that somebody should document on the internet-history list while there are still people around who can do so with some authority. Thanks. -- "Government big enough to supply everything you need is big enough to take everything you have." Remember: The Ark was built by amateurs, the Titanic by professionals. Requiescas in pace o email Ex turpi causa non oritur actio Eppure si rinfresca ICBM Targeting Information: http://tinyurl.com/4sqczs http://tinyurl.com/7tp8ml