The Traditional Approach
The Best Practice Approach
Create port-based rules and/or IP-based rules, which provide sufficient security in the trusted network.
Port-based and IP-based rules can’t control which applications to allow to connect to the internet. If a port is open, any application can use the port.
Create strict application-based whitelist rules that allow only data center servers that retrieve updates to use only legitimate applications to communicate only with legitimate update servers. Log and monitor whitelist rule violations.
When you transition from port-based to application-based rules, in the rulebase, place the application-based rule above the port-based rule it will replace. Reset the policy rule hit counter for both rules. If traffic hits the port-based rule, its policy rule hit count increases. Tune the application-based rule until no traffic hits the port-based rule for a period of time, then remove the port-based rule.
Data center servers only reach out to trusted servers such as update servers, so decrypting that traffic isn’t necessary.
Malware or command-and-control software that is already in the data center may attempt to communicate with external servers to download more malware or exfiltrate data.
Decrypt all traffic from the data center to the internet. Create a custom URL categories that defines the URLs data center servers are allowed to contact and use it in Security policy to limit internet access to external servers. Use the same custom URL in Decryption policy to decrypt traffic to those external servers.
Mix blocking and alerting threat prevention profiles from multiple vendors.
A conglomeration of individual tools leaves security holes for attackers and may not work together well.
The Palo Alto Networks suite of coordinated security tools works together to plug security holes and prevent attacks.