Am 23.09.2016 um 19:57 schrieb RW:
On Fri, 23 Sep 2016 13:13:19 -0400
Sean Greenslade wrote:
On Fri, Sep 23, 2016 at 05:03:00PM +0100, RW wrote:
I've been wondering whether recursive is actually the correct term.
As I understand it there are two types of DNS lookup:
1. Iterative - where results are found by working down through
multiple servers from the root servers.
2. Recursive - where a request is made to a single nameserver
which handles the whole look-up on behalf of a client.
What this turns on is whether a forwarding server is a distinct
class of of nameserver or a type of recursive server. I think the
latter is most logical, since both provide a recursive interface.
Definitions of the term "recursive server" that I've seen contrast
it only with "authoritative server".
One thing is certain, what you want is a name server that does
*iterative* lookups.
A forwarding server is a recursive server. The two are more or less
synonymous. Both iterative and recursive servers may or may not cache
their results to speed up future queries for the same information.
A nameserver that does iteration is definitely a recursive server. To
say that "recursive server" and "forwarding server" are more or less
synonymous is wrong
well, that whole stuff is discussed way too complex here
your nameserver can do recursion, be authoritative for own zones and
forwarder for specific zones at the same time - the only relevant point
is that it don't forward DNSBL/DNSWL/URIBL relevant questions to a
shared nameserver outside your network - that's it
in context of a inbound mailserver (for anything you don't host on your
machines) it's just as simple as:
* if your DNS is aksing another DNS you defined you are doing it wrong
* if your DNS configuration contains another dns server it's wrong
* if your DNS server like dnsmasq looks in /etc/resolv.conf it's crap
the one and only ecxeption are large networks where you have a central
caching server doing recursion and on the other nodes you have this
machine as forwarder, but if you are in such an environment you
hopefully understand dns basics anyways
