Most computer systems in the Physics and Astronomy department use internal IP addresses. This means that unless someone is connected to the BYU internal network (on campus or VPN) then they will not be able to access most computers in the department from home or anywhere outside of BYU campus.
However, to access on-campus resources from an off-campus location you will need to install the PaloAlto GlobalProtect client from https://vpn.byu.edu/. Please configure the GlobalProtect client to use vpn.byu.edu. If you are unable to connect to campus via the VPN, you will need to contact the BYU OIT Helpdesk to request VPN access.