I don't know if this can be done, but if I have a router with two ISP WAN connections (ip nat outside), one LAN connection (ip nat inside). Can I send my LAN address range 192.168.1.2 to ...20 to go out one WAN interface and 192.168.1.21 to ...254 to go out the other WAN interface?
Explanation: my servers are all in the lower range and I have outside access (static PAT) to them via the WAN #1 IP address (which is a high speed, expensive [charge-by-the-gigabit] link), so obviously reply traffic has to appear to come from the WAN #1 address. All the workstations on the LAN are on the 192.168.1.21 address and above and I want to send their traffic out WAN#2 because it's a low-cost DSL link
Note this isn't really load-balancing because I want a specific group of IPs on my LAN ONLY to go out on one specific WAN link and another specific group to go out the other specific WAN link.
Is this possible?
I'm thinking probably not but I thought I'd check here before I tell people "no"
Yes it is! It's called Policy Based Routing or PBR. It's pretty easy to configure. Here's a link that should help.
HTH and please rate