How can I access the Central Admin area from and exteranl url?

I would like to access the Central Administration Area from and outside external url.

My internal central admin area is located here:
http://myserverbox:2013/

I would like to access it from an external computer without using RDP at this url:
http://mysite.com:2013/

I have a home server running Windows 2008R2. I tried to open my router port 2013.

But the url: http://mysite.com:2013/ still does not work.

I heard other people like to RDP into the server to access the Central admin area.

Is there another way?

Thank you.