topic Re: Packet capture on physical interface in General Topics

Packet capture on physical interface

msid1978 — Tue, 17 Sep 2019 05:11:33 GMT

I want to take packet capture on the physical interface or the subinterface. Basically I want to check the communication on internal interface. Can anyone help me out ?

Re: Packet capture on physical interface

reaper — Tue, 17 Sep 2019 08:23:04 GMT

hi @msid1978

Check out this article: https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClTJCA0

Re: Packet capture on physical interface

msid1978 — Tue, 17 Sep 2019 23:00:36 GMT

Hi Reaper,

I am new to palo alto and already read the article you referred to. On that article it mentioned

Packets are captured on the dataplane vs on the interface (this explains the next bullet).

I want to capture packet on the physical interface itself, which the document says not possible if I am not wrong. Please clarify if possible.

Re: Packet capture on physical interface

reaper — Wed, 18 Sep 2019 13:27:00 GMT

hi @msid1978

this is correct, but this is an architectual consideration: the hardware architecture is built around the chips on the board, so all packets are forwarded to the dataplane chips for processing and it is there that packets can be intercepted

the only scenario where a packetcapture would not be able to capture a packet, is if they are so malformed that they cannot be forwarded to the dataplane, or (in the case of a larger platform) the packets are part of an already offloaded flow (so if you need to packetcapture an entire session, you need to make sure offloading is disabled)

hope this helps