PAP2T vs RT31P2

[voip123]

Thanks for that suggestion.

I think I need my head examined. Maybe it's because I woke up early this morning and not thinking straight.

I changed my setup (again).

Cable modem -> WRT -> RT

WRT is 172.20.0.1
RT is 192.168.15.1

Connected WRT LAN to RT WAN

On the Internet Setup page, should I have "Obtain IP automatically"? If so, should it get a 172.20.0.x address?

It is not going to work based on what the IPs.

Change you RT IP to 172.20.0.118. It should work.

192.168.15.1 is default gateway of the RT. It is not in the network of the IP 172.20.0.1 belongs to.