Port forwarding when router and modem are separate
Mia Lopez 
I am using two different devices for connecting to the Internet.
I have a Motorola modem and a DLink router, and get my Internet connection from Comcast.
Now I am trying to enable port forwarding to a laptop. Where should I try to do that? Will I need to do that in the router/modem/both? My laptop is going to run over Wi-Fi.
13 Answers
The router. That modem is just going to be giving you an internet connection over your cable line.
You can find more information on how to set up your router for a specific application at portforward.com.
2The problem is modems that aren't just modems, and do NAT
Double NAT is more work with port forwarding and people usually try to avoid double NAT. (i.e. they have just their router device doing NAT).
You could unplug the modem from the wall, connect your comp to it directly, and make sure it isn't giving you a private ip to access its interface. If it is then I suppose it's doing NAT at least to some extent. If the modem is connected to the wall, you brave potentially connecting to the internet directly with just your OS's or other software firewall(comp doing PPP), then you could check more and do ipconfig and tracert to a website, see if any private addresses. Really the ideal may be the modem bridging, otherwise you have double NAT and port forwarding is more work.
An ideal is if your modem is a pure bridge, no NAT. Can even be no PPP. And the Router device you have does PPP(connecting to your ISP).
Your modem looks like it's just a modem
so you just have to configure your router.
I'm not sure how everything is set up, but I can only assume your router only bridges the wireless and wired connections together. You can easily check this if you only have a DHCP server running on your modem.
If that is the case, simply set up the port forwarding on the modem and all should be working fine.
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