DNS Traffic slow/time out after applying Anti Spyware

[rjdahav163]

Hi everyone,

We are using PAN OS 9.1.5.

Our internal hosts and DNS server are in different PA Zones.

We have a policy to allow all hosts to access DNS servers with application "dns".

We used strict anti spyware profile on the above mentioned security policy.

After applying anti-spyware profile, we see that the DNS queries timeout most of the times and very rarely when they work, the queries will take a long time.

As soon as we remove the Anti Spyware profile, everything woks normally.  I am totally lost and cant find the root cause. Since there are no logs as well!!

Is this any known issue? Does anyone else have similar problem?

Thanks!

[SutareMayur]

Hi @rjdahav163 ,

Did you checked Threat Logs? You can verify threat logs with below filter. Also verify the logging configuration on the security policy.

( subtype eq spyware ) 

[MauricioPerez]

HI, are you only applying anti-spyware security profile? If so, you could look at the threat logs and additionally check the packet capture configuration, you may have enabled extended captures on criticalities that do not need it.

[mivaldi]

Your DNS Server is likely sourcing multiple DNS queries re-using the same source port. When this happens and a threat is detected, a DISCARD session is installed, and all subsequent queries 'trip' over the DISCARD session.