Security in Private Web Applications

Hello people.
Our web app must be accessible form about 10 places around the world by
the 50-60 people maximum. Is there any way that this web application is
not accessible for everyone but only for this places and people. I have
heard about VPN Virtual Private Network. Is this maybe the sollution
for this kind of web applications???
(ASP.net, SQL 2008, SQL Server Reporting Services 2008)

Regards, Davor 


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