how to access custom web pages from outside of network .

Hi All,

 I have deployed the custom web pages into the IIS with servername:<portnumber>

Then i have integrated this into the MSCRM 2013 , and accessing this within the same network it's accessible.

but when i am trying to access this from outside the network thess custom webn pages are not accessible from the outside network.

How to resolve this situation and how can i access this from the outside network.