topic Re: Application "Mode Shift" Behavior in General Topics

Application "Mode Shift" Behavior

mgentile — Tue, 20 Sep 2011 18:12:37 GMT

From what I understand, "mode shift" is the term for when an application's identification changes during inspection. For example, a flow may be initially identified as "web-browsing", and then further identified as "facebook". I can't find any documentation about how the "mode-shifted" flow is analyzed again in the security policy. Does the firewall have to parse the entire security policy all over again, or does it first search the initial rule that permitted it for any additional applications, does the box continue inspecting from the initial match rule and down to the the bottom, etc, etc.? Anyone have any ideas? Understanding this behavior could allow for more efficient policy writing.

Re: Application "Mode Shift" Behavior

skrall — Tue, 20 Sep 2011 19:36:55 GMT

The most common example is web browsing that transitions into "Facebook" and then this further transitions into "Facebook chat". If a user is blocked from web-browsing then they will never transition to a more specific aplication. Each time an application transitions to something more specific it is passed through the list of security rules again to see if it should be handled by a different security policy.

I hope this helps.

Steve Krall

Re: Application "Mode Shift" Behavior

mgentile — Tue, 20 Sep 2011 19:54:17 GMT

This is helpful, thank you.