Hey guys i have a modem-router intsalled by local isp here in our country, the thing is it doesn't have any port forwarding or dmz features in it.. Im using the dmz for my cctv network system.. my question is if i installed another router(2nd router as ap dhcp disabled) which has a dmz or port forwarding, will the modem-router(main router) or myu network adopt it? will it work? thanks in advance...
Can you make it work... most likely. Will it solve your issue... no.
You problem is only your main router knows your real IP address. Your second router only knows the address you use on the LAN... in most case private 192.168.x.x You could put the mappings in the second router but it does not have access to the outside it will do little good.
I assume the reason you ask is because your main router contains the modem and your second router does not have the modem function or your provider will not allow you to replace their router
Best bet is to try to get your main router to run as a bridge...ie you are only going to use the modem part and disable the router part. This would then let your second router use a real ip address and do the function as you want. Exactly how you do this depends on the models of the equipment. This is a common question and I suspect your ISP can give you instructions...the key to getting the right information is to use the word "bridge"