Is it possible to do Cross Browser testing without an internet connection for Selenium Grid?

I have been tasked with testing on 'all major browsers' for our off the net application. 

All tested browsers will be installed and be available on our private network.  I believe the big questions are:

• Can Selenium Grid be installed on this network without an internet connection to install the grid?  
• Will the installed Grid be able to then work on the private network?

I'm looking for answers and ideas.  

Thanks.