resolution based on client IP address.

[Kevin Darcy]

There are basically 2 different answers to this question, depending on exactly
what your requirements are:

1) If you're just trying to optimize client/server access, e.g. client pool
A always talks to server B, and client pool X always talks to server Y, all
using the same server name, then you can use the "sortlist" option to sort
them in the correct order, depending on the client's IP address. This assumes,
however, that you have control of *every* nameserver which these clients are
querying, because you'd have to configure the same sortlists in all of them.
Otherwise, you may get some "leakage" or de-optimization, as the
non-sortlist-configured nameservers alternate the order of the answers they
give out for the name from their cache.

2) Otherwise, you'd need to go to a full-blown "split DNS" where you maintain
different copies of the same zone(s) -- each with only 1 A record for the name
-- and run different nameserver instances (at least until BIND 9's
"view" mechanism allows you to run different versions of the same zone within
the same instance). Note that it is possible to run multiple instances of
"named" on a single box, if you have multiple physical interfaces or your
OS supports "virtual" interfaces -- each instance would listen to a different
interface. So you wouldn't necessarily have to dedicate extra *machines* to
the split DNS, although you may want to anyway, because it's probably easier
to maintain that way.


- Kevin

Kariger Enrique-EKARIGE1 wrote:

> Hi All,
>
> I setup an A record with two IP addresses (for the same name). I would like
> the DNS server to resolve to one IP or another depending on the client's IP
> address or at least on the client's subnet. Any idea of how to do this ?
>
> Many thanks,
>
> Enrique.