Palo Alto Networks firewalls automatically generate a packet capture for sessions
that contain an application that the firewall cannot identify. Typically, the
only applications that are classified as unknown traffic—tcp, udp, or
non-syn-tcp—are commercially available applications that do not yet have App-ID
signatures, are internal or custom applications on your network, or potential
threats. You can use these packet captures to gather more context related to the
unknown application or use the information to analyze the traffic for potential
threats. You can also
Manage Custom or Unknown Applications by controlling
them through security policy or by writing a custom application signature and
then creating a security rule based on the custom signature. If the application
is a commercial application, you can submit the packet capture to Palo Alto
Networks to have an App-ID signature created.