NetScaler DNS cached entries are not being used

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Article ID: CTX261078

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Description

Cached entry for domain is found in the NetScaler DNS cache.

NetScaler# nsapimgr -d ALL_AREC | grep xhaus
Index     TTL              IP Host
   29   14400  178.62.232.231 xhaus.com7knes.googlevideo.com
  155   14400  178.62.232.231 xhaus.comoglehosted.l.google.comm

Nstrace shows that DNS request is still sent to DNS server even though there is a cached entry:

49  2019-08-12 12:17:42.705 1.1.1.1   2.2.2.2    Standard query 0x100f A xhaus.com
50  2019-08-12 12:17:42.705 2.2.2.2 1.1.1.1    Standard query response 0x100f A xhaus.com A 178.62.232.231
Name: xhaus.com
Time to live: 14279
Address: 178.62.232.231

Resolution

None - This is expected behaviour
How to verify the records are cached in each PPE, in this example 3 PPE's are assumed:

NS-CLI> show dns addrec -type proxy | grep xhaus.com 
1) Host Name : xhaus.com ECS Subnet : None
2) Host Name : xhaus.com ECS Subnet : None 
3) Host Name : xhaus.com ECS Subnet : None

Problem Cause

NetScaler cache records are per Packet Engine, so if the traffic is handled by a PE and the subsequent record is cached in another PE, then cache miss is expected behaviour.

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