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Date: Sat, 17 Jan 2004 12:16:46 +0200
From: Ruslan Ermilov <ru@freebsd.org>
To: Xin LI <delphij@frontfree.net>
Message-ID: <20040117101646.GD18084@FreeBSD.org.ua>
References: <042601c3dcb0$de90c410$0401a8c0@phantasm205>
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cc: freebsd-net@freebsd.org
Subject: Re: Newbie question: is net.inet.ip.fastforwarding intended for
	routers only?
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On Sat, Jan 17, 2004 at 12:17:48PM +0800, Xin LI wrote:
> As title. To my imagination (I have taken a sight on the kernel networking
> code), the fastforwarding path is intended for routers only, so if I want
> some functionalities, for example, NAT, the fastforwarding is not useful,
> and my experiment shows that if I enable it, ipfilter's NAT will be broke=
n.
> Am I right?
>=20
> Thanks in advance!
>=20
Worse.  From the inet(4) manpage,

: IPCTL_FASTFORWARDING  (ip.fastforwarding) Boolean: enable/disable the use
:                       of fast IP forwarding code.  Defaults to off.  When
:                       fast forwarding is enabled, IP packets are for-
:                       warded directly to the appropriate network inter-
:                       face with a minimal validity checking, which
:                       greatly improves the throughput.  On the other
:                       hand, they bypass the standard procedures, such as
:                       IP option processing and ipfirewall(4) checking.
:                       It is not guaranteed that every packet will be
:                       fast-forwarded.


Cheers,
--=20
Ruslan Ermilov
FreeBSD committer
ru@FreeBSD.org

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