two networks from one modem

[CapyWarrior]

I have one modem and have been thinking of setting up a second network (two routers, independent of each other). Modems only assign one ip address so i cannot just switch to both of them and cascading requires port forwarding both routers which is annoying. However if i were to connect an old router (with the wireless switched off and firewall disabled) to the modem and run the two routers out of the ports on that and open all the ports on the old router (no security risk as the two routers would not be setup this way) I could port forward whichever ports i needed on either network and they would be independent of one another. Does anyone know if this would work and if not are there any alternatives? Thank you.

 

[Emerald]

connect router1 to the modem, assign a static IP address of router1's IP scheme to the WAN side of router2, and then enter the static IP of router2 in the DMZ of router1.

if both router LAN IPs are the same, you will have to change the one on router2 to a different IP scheme.

router1 LAN IP: 192.168.1.1
router1 DMZ entry: 192.168.1.253
router2 WAN IP: 192.168.1.253
router2 LAN IP: 192.168.0.1

 

[CapyWarrior]

connect router1 to the modem, assign a static IP address of router1's IP scheme to the WAN side of router2, and then enter the static IP of router2 in the DMZ of router1.

if both router LAN IPs are the same, you will have to change the one on router2 to a different IP scheme.

router1 LAN IP: 192.168.1.1
router1 DMZ entry: 192.168.1.253
router2 WAN IP: 192.168.1.253
router2 LAN IP: 192.168.0.1

Will this solution allow me to only have to port forward one router?

 

[Emerald]

No you need to port forward on both router for of the IP schemes.

for for devices connected to router1 you only need to do the port forward on router1.
for devices connected to router2 you only need to do the port forward on router2.

putting router2 in to the router1 DMZ is like connecting it directly to the modem; therefore, you don't need any port forward on router1 for devices connected to router2.

 

[Alabalcho]

Your idea would work if your current routers are actually "router" and not "gateway" - that is, you can put routing rules on the WAN interface.