On 2/14/2010 6:21 PM, Scott Howard wrote:
A "resolver" is basically a client.
There's two types of resolvers - recursive resolvers (that look after doing the full resolution themselves - starting at the root servers and working down), and "stub resolvers" which are only smart enough pass the entire request onto another server to handle.
On most system, the "code in your local machine" will be a stub resolver. That's why you need to configure it to point to another server that looks after the actual recursion for you.
That is another piece that I had glossed over--the "client" side of a server.
The "DNS Server" running at your ISP that your stub resolver connects to is acting as both a server (to accept requests from your client), and as a resolver (to actually resolve those requests), and almost certainly also as a cache for results. For simplicity, many people simply refer to them as Resolvers, whilst others call them Recursive servers or Caching servers.
Calling any form of server a "resolver" seems new to me--or my lack of understanding is older that I like to admit.
The server actually answering the requests for your domain is an Authoritative Server. An Authorative-only server doesn't ever act as a client, so it isn't a resolver.
It is possibly to run both Authoritative and Recursive server on the same IP, but it's generally not recommended for many reasons (the most simple being that of stale data if your server is no longer the correct nameserver for a domain, but it's still configured to be authoritative for that domain).
Seems like TTL management would take care of that but I think the issues of recursion are now different from the safe world I thought I lived in 20 years ago. 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