SBS Server has ISA installed and is using Packet
Filtering. The client PCs can connect to the Internet (via
Web Proxy) and can download Anti-virus updates (MS
FireWall Client installed). But the actual SBS/ISA cannot
have the FireWall Client installed, so cannot download the
anti-virus updates or use other services which are not
covered by the Web Proxy.
SBS does have two NICs, for Internal and External network.
How can ISA, network or Routing be configured to allow the
ISA access to these services?