The gli should sort its own connection between it and the outside world but make sure your LAN IP is DIFFERENT NETWORK but on the same subnet.
EG my gli to phone connection could be 192.168.10.xxx/255.255.255.0, the gli internal LAN IP and DHCP pool should be on another network and SAME subnet like 192.168.9.xxx/255.255.255.0. All devices within use that pool.
If you have another router between the gli an outside then you need to put the gli LAN IP into THAT routers DMZ OR activate UPNP/open ports.
Gateways point to the next router, not the overall Point Of Entry. DNS points to the POE.
Hope this helps.