I have a SMCD3GNV modem. I am tring to hook up a Verizon wireless network extender for business (model # SCS-2U3100). I have done some research and have gotten as far as I can get. What I found is QOS Mode enabled, IPSEC or IPSEC Pass Through enabled, Port Forwarding 53 tcp/udp 500 udp 4500udp 52428 udp, and DHCP settings ip range 10.x.x.x shouldnt be used, if used change subnet mask to 225.255.255.0.
I have forwarded the ports, but i can not change the subnet mask, it gives me 3 optons to change it to and none are 225. I can not find QOS mode, or IPSEC anywhere. I have considered changing the IP range but not sure if that will mess up the modem, or everything else on the network.
Completly lost on this one, usally can figure this stuff out, but new to Xfinity modems.