Access external ip from internal IP DPC3939B

I need to be able to access my external IP from an internal one. Currently when I try to, I am unable to access my private web server. I can access it locally and from a remote IP, but not from a local ip (EX: 10.1.10.10) to the external IP. Is there a setting I can change on the DPC3939B to allow this? I'm not seeing no option for it in NAT nor does static routs work.