[lug] Routing with Linux

[Bonnell, Doug]

Forwarding is needed, but I would think that ipchaining would be
nice to use also.

I don't have the exact syntax handy, but if net1 is on Linux eth0
and net 2 is on Linux eth1, then:

     ipchain FORWARD 192.13.5.6/40 eth1      (net1 forwarded to net2)
     ipchain FORWARD 207.16.8.9/37 eth0      (net2 forwarded to net1)

This saves telling all the machines where packets need to go. You'll
need routing at the individual machines on each net.

     route add -host finkel -gw rupert      (finkel on net2, rupert = net1
Linux IP)

     route add -host narn -gw turtle        (narn on net1, turtle = net2
Linux IP)

First example for a machine on net1 needing to get to finkel on net2.
Second is for a machine on net2 needing to get to narn on net1.

I think of this more as a bridge than a router since it links to subnets
together
rather than a single connection to a subnet.

Hope this helps,
Doug Bonnell

> -----Original Message-----
> From:	Sean Reifschneider [SMTP:jafo at tummy.com]
> Sent:	Thursday, June 29, 2000 3:51 PM
> To:	lug at lug.boulder.co.us
> Subject:	Re: [lug] Routing with Linux
> 
> On Thu, Jun 29, 2000 at 09:43:46PM +0000, Stephen G. Smith wrote:
> >Network 1 is a 35 node public static IP network
> >Network 2 is an 8 node public static IP network
> 
> No problem.  Simply take a Linux machine with two interfaces, and plug
> one into each network.  Assign IP addresses to each interface, and
> enable packet forwarding on that machine.  It's now acting as a
> router between them.
> 
> Now you just have to tell the 35 machines on net1 that any packets
> destined for net2 go to the IP address of the Linux machine's
> interface on their network, and the converse for the machines on
> net2.
> 
> Or, if you have a router that's acting as your default gateway
> (connection to the internet most likely), you can tell it to
> do the forwarding so you don't have to change routing on all the
> other machines.
> 
> Sean
> -- 
>  ISA isn't dead, it's just that people wish it were.  The correct term for
>  this condition is "legacy"...  --  Sean Reifschneider, 1999
> Sean Reifschneider, Inimitably Superfluous <jafo at tummy.com>
> tummy.com - Linux Consulting since 1995. Qmail, KRUD, Firewalls, Python
> 
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