transparent DNS load-balancing with a Cisco ACE

[John Miller]

Thanks Daniel.  Good to hear of someone using NAT for DNS traffic.  My 
fears of it are mostly performance-based--every DNS query takes up a new 
entry in the ACE's NAT table.  In our case, that's thousands of queries 
per second that the ACE has to keep in memory.  I've shown it to be a 
slight (25% or so) performance hit in terms of max queries/second.

At this point, these are recursive-only servers, so I'm not even worried 
about zone transfers--that piece of the project comes next!  The 
rservers will be doing a bunch of outbound queries, however, and using 
their real addresses for that.

John

On 10/19/2012 04:32 PM, Daniel McDonald wrote:

> I've not bothered with nat - just place rservers with unique addresses
> behind the ACE, let them use the ACE as their default gateway, and then
> publish a vip.  The rservers use their real address for zone transfers with
> the master, while clients only talk with the vip address.
>
>