Femmebones

I'm trying to configure my own server so I can play with friends but I'm having trouble configuring my ports correctly. I am using a NETGEAR router, by the way. I have successfully ran other private game servers but I must be missing something this time around. After forwarding ports through my router and modem, I can't get specific ports to open up for me. For instance, I forwarded all ports 27010-27016 and they all opened except for 27015. I'm having the same issue with port 777. I've configured my firewall correctly, as well as turned it off temporarily to troubleshoot. I am using Port Checker. I also tried checking the server list just in case my server was in fact showing up, but it wasn't. I've literally spent all day browsing through tutorials and help topics but I can't figure it out. I have repeated these steps and am in need of some fresh eyes. Hopefully someone out there will have an idea how to help me! Thanks.