dual homed host

[Robert Puyol]

Hi:

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. From some reading of the FreeBSD documentation and 
gooooooooooogle, here are my questions:

0) do I need to do a sysctl net.inet.ip.forwarding=1 to get a working 
dual homed host ?
1) I set an alias (private IP to use the ISP2): "ifconfig rl0 inet  
10.0.1.4 netmask 255.255.255.0 alias", the I can ping 10.0.1.4 but not 
the router at 10.0.1.1. What's wrong ?
2) I set route: "route add -net 10.0.1/24 10.0.1.1 0", but yet I am 
still not able to ping the router at 10.0.1.1 or to ping my public IP 
from another network.

If I set the defaultrouter=10.0.1.1 (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...

Thanks a lot for your help.
-- 
Robert Puyol