TG852 Modem Bridged with Dlink AC3200 Port forward not working

[Sam Proasheck]

Ok, im new to this forums thing, but i ran into a problem recently thats driven me nuts. I currently have a plan of 50mbps down/6 up wired connection.

To start off, i have comcast and they supplied me with their (not so) awesome TG852 modem. Basically the wifi sucks. So i got a Dlink AC3200 ultra tri band router, and i connected it to the tg852 via cat6(or 5e i dont really know). Everything works fine, perfect speeds etc. Except that i cant port forward. For some reason the only way to do it is to use the really crappy TG852 with the even crappier xfinity firmware, but im not doing that because why did i buy the AC3200. I have tried port forwarding many stuff, like steam 27015, tunngle 11155, nothing seems to be open, and i have the services open when i test it on canyouseeme.org aswell. and i have tried it with wired aswell, to no avail.

Before that one guy asks heres my pc specifications:
Dlink DWA-552 extremeN desktop adapter
gtx 680 4gb(idk why these are relevant)
Amd phenom ii x4 965 oc@3.8ghz
8gb ram

Heres a picture to show you guys that i am (atleast in my knowledge) doing it right:
http://i.imgur.com/a2l6US4.png - you can clearly see that tunngle is open on the taskbar btw.
so my question is: how do i go abouts port forwarding on a router that is connected to the TG852?
By the way i think its called bridge mode or something? but im not sure. anyways, thanks!
UPDATE: I also have the firewall inboud-outbound rules set up and the public/home rules set.

 

[Sam Proasheck]

Ok guys i have been looking around and i will try and set the AC3200 in a DMZ in the TG852. but i will come back tomorrow to try that because currently its 1 am ^^.

 

[BuddhaSkoota]

Ok, im new to this forums thing, but i ran into a problem recently thats driven me nuts. I currently have a plan of 50mbps down/6 up wired connection.

To start off, i have comcast and they supplied me with their (not so) awesome TG852 modem. Basically the wifi sucks. So i got a Dlink AC3200 ultra tri band router, and i connected it to the tg852 via cat6(or 5e i dont really know). Everything works fine, perfect speeds etc. Except that i cant port forward. For some reason the only way to do it is to use the really crappy TG852 with the even crappier xfinity firmware, but im not doing that because why did i buy the AC3200. I have tried port forwarding many stuff, like steam 27015, tunngle 11155, nothing seems to be open, and i have the services open when i test it on canyouseeme.org aswell. and i have tried it with wired aswell, to no avail.

Before that one guy asks heres my pc specifications:
Dlink DWA-552 extremeN desktop adapter
gtx 680 4gb(idk why these are relevant)
Amd phenom ii x4 965 oc@3.8ghz
8gb ram

Heres a picture to show you guys that i am (atleast in my knowledge) doing it right:
http://i.imgur.com/a2l6US4.png - you can clearly see that tunngle is open on the taskbar btw.
so my question is: how do i go abouts port forwarding on a router that is connected to the TG852?
By the way i think its called bridge mode or something? but im not sure. anyways, thanks!
UPDATE: I also have the firewall inboud-outbound rules set up and the public/home rules set.

Ok guys i have been looking around and i will try and set the AC3200 in a DMZ in the TG852. but i will come back tomorrow to try that because currently its 1 am ^^.

As you suggested, place the second router in the first router's DMZ (making sure routers are connected LAN > WAN).
or
Put the first router in bridge mode (port forward from second router).
or
Put the second router in AP mode (port forward from first router).