Quest On Demand Migration - which IP addresses for Firewall rules?

My client is asking to setup a firewall rule to allow traffic from the intranet to the Quest On Demand service.  I can find the ports required, but not the target addresses of the service?  Are they the public IPs of quest-on-demand.com?
Addresses: 108.138.233.111
108.138.233.52
108.138.233.99
108.138.233.83

Cheers

Stuart