app not show on application field on policy based forwarding

[mss.support]

Hi community,

what is the reason one app not show applications field/

We need create one policy with one app that show on applications, but when I check in PBF the app is not show. 

The app name "supremo" use default port tcp/443 and Implicitly Uses:  web-browsing.

What is the reason ?

[Brandon_Wertz · Accepted solution]

The reason is you can't use the full list of apps in PBF that exist in applipedia. It's a misnomer that you can use apps like Facebook or Netflix and "route" those packets.

[Raido_Rattameister · Accepted solution]

Routing decision has to be made based on first packet.

First packet in TCP based application is SYN.

Based on SYN it is not possible to identify application yet and make routing decision.

For example in case of web-browsing application is identified on 5th packet.

SYN - client to server

SYN ACK - server to client

ACK - client to server

HTTP GET - client to server

And now when website sends back website Palo shifts application to web-browsing.

[mss.support]

Cool, thank you.

[Brandon_Wertz]

---

@mss.support wrote:

Cool, thank you.

---

Trust me it was a bummer when I found this as well. 

"Application routing" devices like touted in SD-WAN solutions / Meraki, Viptela, or even Riverbed's SteelConnect tout application based routing.  I've not really delved into these solutions, and can't understand how there isn't some sort of a hit as application shifts occur which could change a routed path.  That said I would love it if Palo could use a similar solution.