Date: Thu, 26 Oct 2000 22:23:39 -0600 (MDT) From: Nick Rogness <nick@rapidnet.com> To: John Telford <j.telford@sympatico.ca> Cc: freebsd-net@FreeBSD.ORG Subject: Re: Multihomed natd, nics and default gateways continued. Message-ID: <Pine.BSF.4.21.0010262159380.29371-100000@rapidnet.com> In-Reply-To: <001701c03fc6$f92d3d60$0100000a@johnny5>
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On Thu, 26 Oct 2000, John Telford wrote: > > natd2 8669/divert # Network Address Translation > > > > Then run the nat`s seperately: > > > > root# natd -p 8668 -n fxp0 > > root# natd -p 8669 -n fxp1 > > The proper place to have these load at boot would be rc.conf or rc.local or It's really up to you, but rc.conf is probably the best place. In /etc/rc.conf: defaultrouter="NO" static_routes="0 1 2" route_0="-net 0.0.0.0 -netmask 128.0.0.0 AAA.AAA.AAA.AAA" route_1="-net 128.0.0.0 -netmask 128.0.0.0 AAA.AAA.AAA.AAA" route_2="default BBB.BBB.BBB.BBB" Where AAA.AAA.AAA.AAA is the default gateway for ISP A and BBB.BBB.BBB.BBB is the default gateway for ISP B. > ? > > > > For routing: > > > > Add 2 default routes, one primary (ISP A) and one backup (ISP > > B). Since ISP A is a prefered route...it gets the more specific > > route: > > > > root# route add -net 0.0.0.0 $GATEWAY_IP_ISP_A -netmask 128.0.0.0 > > root# route add -net 128.0.0.0 $GATEWAY_IP_ISP_A -netmask 128.0.0.0 > > > > root# route add -net 0.0.0.0 $GATEWAY_IP_ISP_B -netmask 0.0.0.0 > My tcp/ip is weak, how does applying a route for 128.0.0.0 work here ? or > what happens in the box if ISP_A goes down ? What happens is traffic normally flows to ISP A because it has a more specific route to get to a any given network 0.0.0.0/8 & 128.0.0.0/8. The reason for this is because FreeBSD doesn't have support (yet) for 2 routes to the same network. Since 0.0.0.0/8 & 128.0.0.0/8 are more specific routes to the 0.0.0.0/0 network they take precedence. However, if ISP A becomes unreachable, FreeBSD will mark the route for those networks (0.0.0.0/8 & 128.0.0.0/8) as unreachable. This will force routing to use the next specific route (0.0.0.0/0) to be triggered and traffic will start to flow across to ISP B and start using the natd2 address translation. This is not a prefect design. Some things will break during the switch-over (like FTP during a file transfer). However, things should work after the switch over. Nick Rogness - Drive defensively. Buy a tank. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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