03-28-2017 03:53 AM
A bit confused now :0
My policy as below:
So port 80 is allowed when l attempting to connect to the device over the web browser (Chrome) but after Palo actually identified that this is not a "panos-web-interface" app (based on tcp 3 way handshake and some data) didn't the response to the request. I understood that there is no other way to do it unless you got a sufficient data to identified the app hence fist packet is allow based on destination port and session is created.
Another policy snip:
This may not be the best example but for "http-video" (along with other app`s) my Depends on Applications: web-browsing.
My question is what is classified as a web-browsing (it is purely any web-browser request or something more specific) and what else will be allowed if my policy permit two application: https-video and web-browsing? What if l will be surfing the lnternet over the Chrome doest it means that any web-browsing traffic (requests) is allowed and will be successful ?
03-29-2017 12:45 AM
The child app depends on the parent, because the child can only be identified _after_ the parent has been identified by AppID (the first thing AppID sees is the parent's behavior, so identifies as the parent, then the session starts to send child payload and AppID can change to the child app)
The parent app is sort of the transport layer for the child app
03-28-2017 05:14 AM
any web based application will usually start off as web-browsing (hence the whole dependency thing)
when you start any web based session you'll first have the 3 way handshake, which does not permit you to identify any application short of using port 80, next comes a http get (this is web-browsing)
if all you are getting is an average website, the application will remain web-browsing
if, however, you go into more specific applications (http-video , facebook,.. ) AppID will change the application to what is most accurate
so for an application that has a dependency, it means that there is no way (for AppID) to anticipate the application will become the final application, without first having been the dependency app
hope this makes sense?
03-28-2017 07:41 AM - edited 03-28-2017 07:56 AM
Thanks for clearing this up for me. Hmm. I thought in a bit different way. Let's say l do have an app dependent on the web-browsing (assume it is http-video as in out example). For http-video traffic/application to work you must meet both (web-browsing and http-video) criterias however, if you are only meeting one criteria (especially when hitting dependent application only) in our case it is web-browsing traffic will not be permitted (after the firewall clearly identified that the app is pure web-browsing). When the session is created on PA, in the monitoring tab we only able to see a final application as a result of the session id engine scan? When we do > show session id xxxx in the application field the app won't change or it can if l change the application from web-browsing to http-video:
Or it is going to be a completely new session? Hope l am not confusing you or anyone or talking s**t:0
03-28-2017 09:38 AM
03-28-2017 11:27 AM
The majority of the sessions that I deny I have log-start and log-end set to yes exactly for this reason. I like to be able to show to people that while we do block certain applications (bittorrent) it takes a quick second to actually id the traffic. That way when I get the lovely copyright notices I can argue with them about the legitimacy of the claim 😉
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