Configure RH6.2 box as a router

[Jeff CTR Vandenbussche tc faa gov (Jeff CTR Vandenbussche)]

     I have one box I got preloaded with 6.2 from VAlinux and another one 
     that came preloaded with 6.2 from Penguin Computing.  They both have 2 
     ethernet cards (eepro100's) As far as I can tell I have setup 
     networking identical on both boxes.  However my network manager 
     Netview for AIX running on a third box, detects both eth0 and eth1 on 
     the VAlinux box, but only detects eth0 on the Penguin box.  I have 
     contacted Penguin, but they are stumped( as am I ).  
     
     It looks like the VAlinux box is being detected as a router but the 
     Penguin box is not.  Can anyone help me set up the Penguin box to act 
     as a router? How does on set up IP forwarding?  Is all that has to be 
     done is change /proc/sys/net/ipv4/ip_forward from 0 to 1, or change 
     this is /etc/sysctl.
     
     Any help would be greatly appreciated.  I am currently scheduled to 
     send these boxes to the customer's site next week, so I don't have 
     much time to figure this out.
     
     Thanks,
     
     Jeff