Getting intermittent unknown UDP traffic logs

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Getting intermittent unknown UDP traffic logs

L3 Networker

Hi All ,


I am having policy  having application group and set services as application default .


Sometime policy is working fine but sometime its dropping packet and in logs showing application  unknown UDP.


Could you please suggest any troubleshooting steps here ? I did packet capture but not seeing any this specific which can indicate any issue on firewall end .




Cyber Elite
Cyber Elite


What type of traffic are you actually seeing this on? It wouldn't be uncommon to see something developed internally have an unknown-tcp/udp determination, but if it's traversing the untrust/internet interface that's different. 

In any case, it usually means that the firewall either didn't pass enough traffic to identify the app-id, or an app-id simply doesn't exist for the traffic. 

@BPry ,

It's syslog traffic . Moreover for same set of source and destination IP , its working fine , properly identifying the APP-id.

I am using default syslog app-id .


Interesting. I've never actually had the firewall fail to identify syslog traffic across the default 514 port, but I have if I customize the port without creating a custom application or doing an application-override see it come across as unknown-udp. 

Personally, I would take a packet capture of the traffic when it comes across as unknown-udp and see if you can notice any sort of difference with the traffic. If you aren't seeing anything I would try to capture the traffic and open up a TAC case for review.



Thanks , I will check with Tac and update here with findings .

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