I am in the planning stages of a VPN solution for my company. Currently, my gateway to the Internet is a Windows NT 4.0 Server with 2 NIC's. This server is my PDC for the network. This Server also runs IIS 4.0, Proxy Server 2.0, and Exchange Server 5.5. I want to upgrade the box to Windows 2000 Server, which according to other documentation I have read, will automatically upgrade my IIS to ver. 5. Can I upgrade the Proxy Server to ISA Server on this box and keep Exchange 5.5 running on this server as well? Thanks.