Acessing Portal Over Internet

Hi

Can any one pls let me know how to access my portal over internet..

As of now my portal is runnig in lan, no issues in this.

But i want to acess this portal using internet( out side the network) by using any datacard(tata photon r reliancenetconnect) or using internet.

so what is the process to be followed and what are the configurations to be done to achieve this .

pls let me know which is very help ful to me

Thanks

Sandeep Kumar