01-24-2011 04:31 AM
Hi All
I have come across a problem with our ACE service modules. This is performing DNS load balancing with our servers, which is working fine, with the exception of the following order of events;
The client tries two queries in quick succession for A and AAAA records, the ACE is closing the SLB session the instant a DNS answer comes back. This is causing problems with clients that make 2 lookups very quickly, from the same source port.
The ACE module is running A2(2.4).
Any help much appiracted.
Regards MJ
01-24-2011 12:02 PM
MJ,
Are you using DNS inspection?
Chris
01-24-2011 12:42 PM
Hi Chris
Thanks for the response, yes DNS inspection is in use.
Regards MJ
01-26-2011 05:37 AM
MJ,
If this is a non-production environment, I would try to turn on DNS inspect. DNS inspect checks to ensure there is only one DNS request per connection. If the second request is hitting the ACE prior to a response for the first then the second request will be dropped. If it works without DNS inspect enabled, I would ask that you open a TAC case so we can gather addtional data. In the meantime you can see DNS inspect errors with the following commands:
sh np 1 me-stats "-sfixup -v"
sh np 2 me-stats "-sfixup -v"
Thanks
Chris
01-28-2011 02:12 PM
Hi Chris
Thanks for the update, I have tried with DNS inspection disabled but this is still the case.
Regards MJ
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