Cisco Distributed Director

Dan Considine dconsidine at exchange.ml.com
Fri Jun 16 20:31:21 UTC 2000


Here's the environment.

Primary DNS server (Bind 4.9.7 / Solaris 2.6)
Secondary DNS server (Bind 4.9.7 / Solaris 2.6)

Distributed Director (Cisco IOS 11.1.(20)IA)

I have delegated dd.us.ml.com from my DNS servers to
the DD

dd.us.ml.com IN NS  wfddd1.ml.com
   IN NS  huddd1.ml.com

On the DD I have a director host setup with 8 ip's with
equal portion metrics,  TTL = zero

wfdbbsocks-p.dd.us.ml.com (8 ip addresses)

Clients have the following:

Primary and Secondary DNS servers setup as their resolvers.

Start Openbloomberg, config file states wfdbbsocks-p.dd.us.ml.com
as it's socks server.

Client tries to resolve socks server by way of resolvers,  resolvers
go to the DD (wfddd1 or huddd1) to get an A record,  DD returns an ip
by way of equal portion metrics (round robin),  resolver returns ip
to client and caches this A record with a TTL of zero.  Now,  this is
fine on a client by client query,  works fine.  The problem is when we
restart our proxy servers.  We have 3,000 users connected over the 8
machines,  once the client loses it's connection it tries to get another
ip.  So,  we have 3,000 queries sent to DNS,  DNS starts handing out the
last cached ip while it tries to get another 1 from the DD, by this time
it's too late,  maybe 500 clients already received the same ip which
defeats
the round robin setup.  I need to find a way to have our DNS servers send
the client to the DD for the A record (non-recursive dns).


Dan Considine wrote:

> Is there a way to setup non-recursion on an NS record in Bind 4.9.7?  I
> need to have client queries sent to my Distributed Director for
> resolution,  TTL on the Director is set to "0",  root server takes 1
> second to cache this record which
> defeats the purpose of the "0" TTL.    Any ideas?
>
> Thanks in advance,
>
> Dan.





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