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Date:      Mon, 2 Jul 2001 11:51:29 +0300
From:      Ruslan Ermilov <ru@FreeBSD.ORG>
To:        Wes Peters <wes@softweyr.com>
Cc:        net@FreeBSD.ORG
Subject:   Indirect route with also indirect gateway (was: Re: fastforwarding?)
Message-ID:  <20010702115129.A67459@sunbay.com>
In-Reply-To: <3B3F930C.320CC3DC@softweyr.com>; from wes@softweyr.com on Sun, Jul 01, 2001 at 03:15:56PM -0600
References:  <GPEOJKGHAMKFIOMAGMDICEOJDGAA.deepak@ai.net> <20010626093545.D49992@sunbay.com> <3B3AB4F8.184A2EFE@softweyr.com> <xzp1yo4wdjh.fsf@flood.ping.uio.no> <20010629112757.F91115@sunbay.com> <3B3F930C.320CC3DC@softweyr.com>

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On Sun, Jul 01, 2001 at 03:15:56PM -0600, Wes Peters wrote:
> Ruslan Ermilov wrote:
> > 
> > BTW, Wes, I'm still waiting for a working example of an indirect route
> > with also indirect gateway.
> 
> Any indirect route via the opposite end of a point-to-point connection.  
> Right?
> 
You probably meant that the gateway is accessible via the opposite end.

But the gateway value on a P2P link is a no-op.  Whatever gateway you
specify, the actual gateway is always the "opposite end".  Here, the
gateway only helps the routing code to select the right interface.
I.e., on a 1.1.1.1 -> 2.2.2.2 configured tun0 interface, the following
two commands are equivalent:

route add -net 10 2.2.2.2
route add -net 10 -iface tun0

Funny though that you're giving this example, as it only works starting
with revision 1.62 (from June 4, 2001) of sys/net/route.c.  Before this,
routing code incorrectly set up the interface based on destination, not
the gateway:

# ifconfig tun0
tun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> mtu 1500
	inet 1.1.1.1 --> 2.2.2.2 netmask 0xff000000 

# netstat -rn
Routing tables

Internet:
Destination        Gateway            Flags     Refs     Use     Netif Expire
default            192.168.4.65       UGSc        1        0     rl0
2.2.2.2            1.1.1.1            UH          0        0    tun0
3.3.3.3            tun0               UHS         1        0    tun0
127.0.0.1          127.0.0.1          UH          1        6     lo0
192.168.4          link#1             UC          3        0     rl0 =>
192.168.4.65       0:d0:b7:16:9c:c6   UHLW        2     1576     rl0    899
192.168.4.115      0:c0:df:3:2d:79    UHLW        2        2     lo0

# route add -net 10 3.3.3.3
add net 10: gateway 3.3.3.3

# netstat -rn | grep 3.3.3.3
3.3.3.3            tun0               UHS         1        0    tun0
10                 3.3.3.3            UGSc        0        0     rl0
                                                                ^^^^ oops

I still think we should disallow such routes on non-P2P interfaces, at
least.  What do you think?



Cheers,
-- 
Ruslan Ermilov		Oracle Developer/DBA,
ru@sunbay.com		Sunbay Software AG,
ru@FreeBSD.org		FreeBSD committer,
+380.652.512.251	Simferopol, Ukraine

http://www.FreeBSD.org	The Power To Serve
http://www.oracle.com	Enabling The Information Age

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