Possible? Name into multiple IP addresses.

[Kevin Darcy]

Barry Margolin wrote:

> In article <3860E20C.D5048636 at jobpilot.pl>,
> Grzegorz Strzalkowski  <strzalkowski at jobpilot.pl> wrote:
> >I would like to create one domain name
> >(i.e. www.somethin.com ) and have assigned
> >several IP's to this name. The IP which will
> >be returned on IP-query will be the IP of server
> >which is closest to someone who asks.
>
> Get a Cisco Distributed Director.

On the other hand, if you're on a limited budget, create a round-robin name with
all of the addresses and then define "closeness" via sortlist statements on all of
the nameservers answering for the name.

The drawbacks of this approach are a) unless you can configure the sortlists on
all of the slaves for the zone, and all of the servers caching the round-robin
name, many clients will get improperly-sorted answers and go to the
"wrong" server, b) on very complex networks, e.g. the Internet, the sortlists may
become unmanageable. You can mitigate the effect of (a) somewhat by lowering the
TTL's on the round-robin records, but only at the expense of increasing traffic to
your nameservers.

So this "cheap" solution is best suited to internal networks with a high degree of
control over nameservers in the enterprise, and/or plenty of nameserver/network
capacity to handle the excess load caused by defeating caching, and preferably a
fairly simple network topology.


- Kevin