DNS Sinkholing subdomains of known bad domains

L1 Bithead

DNS Sinkholing subdomains of known bad domains

I tried to find an answer for this, but I couldn't find it. If someone has already posted this question, apologies...


I just turned DNS sinkholing and it works as expected for root domains, for example:


nslookup kntsv.nl returns the DNS sinkhole IP of




If I do an nslookup of any subdomain of kntsv.nl, it returns a valid A record, for example:


nslookup testing.kntsv.nl returns the IP of


My question... Why did the dns lookup for the subdomain work but not the root? I would think the Palo would mark *.kntsv.nl as malicious and return with the sinkhole IP.


Thanks in advance for the help.

L7 Applicator

Re: DNS Sinkholing subdomains of known bad domains

When a root domain is malicious, it does not mean that automatically all subdomains are malicious.
As far as I know in the DNS signatures there are only FQDN's and not wildcard entries.
L2 Linker

Re: DNS Sinkholing subdomains of known bad domains

FYI, You should be able to create your own External Dynamic block list and add it to your DNS Sinkhole policy and wildcard the sub-domains if you want.
Like what you see?

Show your appreciation!

Click Like if a post is helpful to you or if you just want to show your support.

Click Accept as Solution to acknowledge that the answer to your question has been provided.

The button appears next to the replies on topics you’ve started. The member who gave the solution and all future visitors to this topic will appreciate it!

These simple actions take just seconds of your time, but go a long way in showing appreciation for community members and the Live Community as a whole!

The Live Community thanks you for your participation!