True test to verify dns sinkhole configuration is correct

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L3 Networker

True test to verify dns sinkhole configuration is correct

 

 Hi Team, 

 

We recently had a support case where a user followed all the guides on the kb and found that the sinkhole feature appeared to be not working. After a few quick tests we determined they had configured it correctly. The issue was the domains noted on some of the articles on the kb which used to be classed as malicious domains are no longer malicious. 

 

For example the article here; 

https://live.paloaltonetworks.com/t5/Configuration-Articles/How-to-Verify-DNS-Sinkhole-Function-is-W...

 

shows a nslookup against a malicious domain. This domain for whatever reason is no longer malicious. We can quickly verify this from the cli of the Palo Alto device. 

 

admin@PA7050> test url sp-storage.spccint.com

sp-storage.spccint.com content-delivery-networks (Base db) expires in 0 seconds
sp-storage.spccint.com content-delivery-networks (Cloud db)

 

This caused the customer to think the configuration was incorrect. 

 

We advised the customer to check the release notes for the Antivirus dynamic updates installed on their device. This is a true test of the current malicious domains and we get the desired results. 

 

avnotes.PNG

Opening these release notes we get the new malicious domains as at todays date. It will include previous ones that are still malicious. But for testing we should use these. 

 

avnotesdomains.PNG

 

There are articles that mention this. But its at the bottom of the article and can be overlooked. This article also lists domains that were malicious that are no longer classed as so. This can mislead users configuring this feature. 

 

admin@PA7050> test url track.bidtrk.com

track.bidtrk.com not-resolved (Base db) expires in 0 seconds
track.bidtrk.com computer-and-internet-info (Cloud db)

 

 

https://www.paloaltonetworks.com/documentation/60/pan-os/newfeaturesguide/content-inspection-feature...

 

Checking the domains in the release notes we get the correct verdict and validate the configuration.. 

 

 

 

 

nslookups, digs or pings against the domains in the av release notes all return the correct verdict and get sinkholed. This is great for reporting as its there in the threat logs. 

 


admin@PA7050> test url hflucas.info

hflucas.info not-resolved (Base db) expires in 0 seconds
hflucas.info malware (Cloud db)

 

 

nslook.PNG

 

This is a great feature to isolate infected hosts on the network and everyone with a PAN device should enable and configure this feature. 

 

Hopefully this article clears up how to verify the configuration. 

 

The links below shows how to enable it. 

 

https://live.paloaltonetworks.com/t5/Configuration-Articles/How-to-Configure-DNS-Sinkhole/ta-p/58891

 

best regards, 

 

 

Robert D 

 

L5 Sessionator

Re: True test to verify dns sinkhole configuration is correct

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