Update Server IP Addresses

Is there a list anywhere of the IP address ranges that the program contacts to get definition updates?

I have a few computers that are mostly blocked from having internet access but I’d like to open up ports on my router to allow them to be able to do virus definition updates.

Thanks.

Nope, but you could use the offline VPS updates: https://install.avcdn.net/vps18/vpsupd.exe

Is there a way to run vpsupd.exe silently?

Not sure about that, wait for one of the devs or submit a ticket: https://support.avast.com/contact (paid versions)