What’s Palo Alto Sinkhole?

It is a security feature designed to detect and block malware communication. It accomplishes this by redirecting DNS requests for malicious domains to a “sinkhole” IP address, which is usually an internal IP or an external Palo Alto IP. This process prevents infected devices from accessing harmful websites. Additionally, it aids administrators in identifying and remediating compromised devices through the logs generated.

For example

• A user receives a phishing email with a link to “www.fakebank-login..com.”
• He clicks the link, which attempts to resolve the domain via DNS.
• The Palo Alto firewall’s DNS Sinkhole detects the domain as malicious using its threat database.
• Instead of allowing the user to connect to the actual malicious site, the request is redirected to a sinkhole IP.
• The connection fails, and the activity is logged, enabling the security team to identify the user’s device and take action.

Here is an Illustration