Date: Tue, 28 Nov 2006 14:07:45 -0600 From: <gschultz@scriptpro.com> To: <questions@FreeBSD.org> Subject: ping through ipfw giving unexpected results Message-ID: <378BFA1E1FEC59458FEB168D1B4BD0075C995A@excsvr003.scriptpro.com>
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I am running ping.exe from a Windows 2003 Server machine through FreeBSD
4.8 running ipfw, to another Windows server. With plr=3D0, I get no =
ping
failures at all, and with ipfw at its defaults I get no successes, so
I'm pretty sure the network is good.
I configured ipfw with various packet loss rates (call it X) in one
direction, _zero loss_ in the other direction. Then I ran ping for
several hundred cycles. This should be sending an ICMP echo request
(with X prob. of loss), and an echo reply (which should always get
through). Therefore, I would expect to see a ping failure probability
of X.
I tried this at plr's from 0.002 up to 0.47, and did the math: ping is
failing exactly (allowing for statistical variation) 1.500 times more
than expected. This is too unlikely to be chance, so I figure the nice
round fraction of additional failures is due to something I don't yet
understand. Can anyone explain this result? Thanks.
No luck searching the Internet or the FreeBSD/search sites.
------------------------------------------------------------------------
-------
FreeBSD rd_bsd 4.8-RELEASE FreeBSD 4.8-RELEASE #0: Thu Oct 2 23:31:46
CDT 2003
root@xfc_group_sim1:/usr/obj/usr/src/sys/MYKERNEL i386
--
Grant D. Schultz
Senior Software Engineer
ScriptPro
5828 Reeds Road
Mission, KS 66202
gschultz@scriptpro.com
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