dual homed host

Chuck Swiger cswiger at mac.com
Sat May 17 18:42:27 PDT 2003

Robert Puyol wrote:
[ ... ]
> My setup is: one FreBSD server, one interface, two ISP, each providing a 
> router. So I would like to set up a dual homed host, to be able use the 
> two ISP.

"Dual-homed" refers to a machine with two physical network interfaces.

> 0) do I need to do a sysctl net.inet.ip.forwarding=1 to get a working 
> dual homed host ?

You'd enable ipforwarding if you wanted the machine to route traffic 
between two or more physical network interfaces...but that's not what 
you have.

> 1) I set an alias (private IP to use the ISP2): "ifconfig rl0 inet  
> netmask alias", the I can ping but not 
> the router at What's wrong ?

If your alias is on the same subnet, you need to use a netmask of, I believe.

> 2) I set route: "route add -net 10.0.1/24 0", but yet I am 
> still not able to ping the router at or to ping my public IP 
> from another network.

Yeah: I don't think what you were trying is going to work.

> If I set the defaultrouter= (ISP2 router on my network) in 
> rc.conf I can use the ISP2 public IP to acces my server, but then I 
> loose the access to the primary IP of the ISP1...

You can only have one static default route.  Fancier routing protocols-- 
specificly, dynamicly link state protocols like OSPF-- are what's 
neeeded for what you're trying to do.


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