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Forum Discussion

MB_271724's avatar
MB_271724
Icon for Nimbostratus rankNimbostratus
Feb 09, 2017

LTM delay with AAAA record request over IPv4?

I have an LTM running 11.5.3 that seems to be causing a delay when a RedHat6 server makes a combined AAAA/A request over IPv4 (only) to a DNS server pool being load-balanced by the LTM. There's a Fa...
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Kai_Wilke's avatar
Kai_Wilke
Icon for MVP rankMVP
Feb 09, 2017

Hi MB,

 

if you don't apply a DNS profile to your Virtual Server, your F5 wouldn't care about A, AAAA or even combined A & AAAA queries. Only the payload size of the DNS query / response would matter in this case...

 

Have you already captured the ingress / egress traffic of your F5 to see if the F5 quickly forwards the DNS request/responses and/or if the client eventually tries to use DNS-over-TCP and needs to wait for TCP timeouts (e.g. DNS payload >= 512 bytes)?

 

Cheers, Kai