Can we use BI 4.0 Client tools with out any VPN

Hi Guys,

We are a very small company and pretty new in business. I have one and only one simple question.

Can we use BI 4.0 Client tools without using any VPN Softwares ?

We are trying to connect to our BI Sand box from another network , although we have assigned and opened the ports.

With in the same network every thing works fine. now we need to know if we are missing anything or the only way is VPN.

Thanks