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Date:      Fri, 16 Mar 2001 09:28:44 -0600 (CST)
From:      Nick Rogness <nick@rogness.net>
To:        Jeroen Ruigrok/Asmodai <asmodai@wxs.nl>
Cc:        freebsd-net@FreeBSD.ORG
Subject:   Re: same interface Route Cache
Message-ID:  <Pine.BSF.4.21.0103160904310.9691-100000@cody.jharris.com>
In-Reply-To: <20010316110803.B12010@daemon.ninth-circle.org>

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On Fri, 16 Mar 2001, Jeroen Ruigrok/Asmodai wrote:

> -On [20010310 04:00], Nick Rogness (nick@rogness.net) wrote:
> >
> >Is anyone working on route caching functionality within FreeBSD?  This
> >would eliminate a lot of problems with using FreeBSD as a router...which
> >seems to be a common role of which FreeBSD seems to fit.  Especially for
> >machine that are dual-homed.
> 
> Correct me if wrong, but if I recall BSD natively already held a route
> cache, although it might not be the best route cache which we could come
> up with.

	Well, I'm sure it does have some route cache functionality but not
	what is considered to be useful.

	I'll clarify real quick for people who are asking 'why?'.  Bare
	with me.  As a packet comes in one interface, there should be a
	way when the packet comes back out to be sent out that same
	interface it was received on, regardless of what the default route
	says.

	For dual-homed hosts, this is a problem because your packet gets
	sent out the default gateway, which may or may not get filtered
	upstream.  This is usually solved by running a routing deamon but
	most upstreams won't allow you to do that anyway (cable,dsl,etc).

	There is a workaround solution involving natd but it is a pain in
	the butt.

> I'll add this to my todo as well.

	I've had some ideas on how someone would implement this.  The more
	I think about it the more I think it should be similar to
	natd.  The packet could be diverted like:

	ipfw divert route-cached ip from any to any in via ed0

	or something similar.  route-cached could be a userland program,
	like natd, with options:

	 - setting different gateways for different interfaces
	 - hold down timers ,etc

	Routes could be added into the routing table accordingly as
	packets come and go via this daemon.  You or someone will have to
	validate this logic.  I may be way off course here...but it was a
	stab.  Maybe it belongs somewhere else.

	I've been preparing to write such a program, going off the base of
	natd.  Please let me know if this is a good idea or not.

Nick Rogness <nick@rogness.net>
- Keep on routing in a Free World...  
  "FreeBSD: The Power to Serve!"




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