Session timeout

[frankieyahoo]

Hi,

From reading this article below:

Connection Timeout Even When Heartbeat Packet Sent

https://live.paloaltonetworks.com/t5/Management-Articles/Connection-Timeout-Even-When-Heartbeat-Pack...

It says "The session timeout is set to 60 minutes"; what does it mean of this sentence? Which timer represents the session timeout value here (set to 60 minutes)?

It says "This means 16 heartbeat packets are required to reset the timeout value."

If the heartbeat interval is 3 minutes. 3x16 = 48 minutes, which is shorter than 60 minutes. Does it mean that it won't encounter this 60 minutes of session timeout?

What is the function of "session offload"?

[kiwi]

Hi,

Session timeout

  TCP default timeout:                           3600 secs

Also this article explains offloading : 

https://live.paloaltonetworks.com/t5/Management-Articles/Why-and-When-are-Sessions-Offloaded/ta-p/61...

Kind regards,

-Kim.

[frankieyahoo]

Hi Kim,

Session timeout

  TCP default timeout:                           3600 secs

Function of this timer, does it mean that if the TCP session has no activity or no any new packets exchange within this 3600 seconds (1 hour), then the TCP session will be dropped (TCP aged-out)?

But if there are heartbeat packets communicating within this 1 hour, why this TCP default timeout could still take effect after 1 hour? Or heartbeat message can not be counted as monitored packet here? 

[TranceforLife]

Good question. l want to hear reply as well 

[kiwi]

That is correct.

For offloaded TCP sessions the following rules apply :

# TCP session, 16 packets per flow (i.e. 32 packets per session, bi-directional) is needed to refresh session TTL timer.   This is a performance consideration.

In addition to the mentioned workarounds in the first article you posted you could also disable offloading.  Note that this approach can have a noticeable impact on the CPU and is not recommended.

-Kim.