topic Re: PA-5250-AC Policy Rule, Service: Application-default for DNS Application in General Topics

PA-5250-AC Policy Rule, Service: Application-default for DNS Application

RVizcarra — Fri, 23 Jul 2021 17:28:35 GMT

I have my PA-5250-AC with below sample rule. As per checking the traffic logs, I found out that UDP 53 is hitting rule 2 while TCP 53 is hitting rule 1. what is the possible cause?

No.

Source

Destination

Application

Service

…

dns

…

Application-default

Any

made some research and found this article that says DNS, application default only matches TCP 53 but as checked with Applipedia
standard ports is tcp 53, udp 53, 5353.

https://docs.paloaltonetworks.com/pan-os/9-0/pan-os-admin/policy/security-policy/components-of-a-security-policy-rule.html#

Re: PA-5250-AC Policy Rule, Service: Application-default for DNS Application

kiwi — Thu, 29 Jul 2021 06:35:57 GMT

Hi @RVizcarra ,

When checking the logs, is the application actually being identified as DNS ?

Cheers,

-Kiwi.

Re: PA-5250-AC Policy Rule, Service: Application-default for DNS Application

OtakarKlier — Thu, 29 Jul 2021 14:31:20 GMT

Hello,

When it comes to external DNS, only your internal servers should be communicating with the secure dns providers you specify. This way you cant have data exfiltration over port 53 to some external source.

Regards,