The following recommended best practices network setups were prepared by Merv Porter, Small Business Computer Networks.   

The recommend practice for attaching a Server to a high speed access is to use two Network Cards.  One will be used for the Internal Network LAN connection, one will be used for the External Network LAN connection.

     SBS 4.5, 2 NICs, Static IP, Proxy Server, No Router

     SBS 4.5, 2 NICs, Static IP, Proxy Server, Router

     SBS 4.5, 2 NICs, Static IP, Proxy Server, T1 Router

     SBS 2000, 2 NICs, Static IP, ISA [Proxy Server], No Router

     SBS 2000, 2 NICs, Static IP, ISA [Proxy Server], Router

     SBS 2000, 2 NICs, Dynamic IP, ISA [Proxy Server], Router

     SBS 2000, 2 NICs, Dynamic IP, RASPPPoE software, no Router

     Basic setup instructions for SBS 2000

     How to Maintain a Secure SBS Installation:
     http://support.microsoft.com/default.aspx?scid=kb;en-us;Q303323&&GSSNB=1