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Date:      Fri, 31 Aug 2012 02:26:47 -0400
From:      CSS <css@morefoo.com>
To:        freebsd-pf@freebsd.org
Subject:   active pf states vs. active connections
Message-ID:  <35E5558A-6AF6-4E67-8FF9-70C74B9EB5D0@morefoo.com>

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Hello,

We've recently been seeing issues when creating a large number of =
outbound connections where the number of states kept by pf seriously =
outnumbers the number of actual connections as shown by netstat.  It's =
not terribly surprising - the kernel has different timeout values than =
the firewall.  However as I've been slowly moving the pf timeouts down =
(mainly on finwait entries), I'm not seeing the number of states really =
shrink.

For example, we might see about 200 connections in FIN_WAIT_2 in =
netstat, but over 20,000 tracked in pf, even with the tcp.finwait =
dropped down to 5s.

It's a problem I never really thought about before - how to address the =
inherent difference between the how aggressively the kernel ages old =
connections out vs. how aggressively pf times them out.

Before I hit the list with a bunch of stats, I just wanted to get a feel =
for whether I'm on the right track here - should I essentially be =
turning down pf timeouts to match kernel tcp timeout parameters?  If I =
should, why am I seeing so many lingering state entries?

This is FreeBSD 8.3.

Thanks,

Charles=



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