securing inside perimeter

["k. frisco" <kfrisco @ shrike . depaul . edu>]

Here's my dilemma:  

external web server ----application---inside web server---sql database
                         firewall          |
                                           |
                                       betrieve server


Need to allow access to inside web server to thousands of untrusted
clients.  This will dynamically update both the sql database and the
betrieve files.  Also need to authenticate before(?) hitting inside web
server.  

TIS suggested using smartgate.  Does anyone have any other suggestions or
can anyone give me their opinions on smartgate.  Is anyone else using
smartgate for over 90,000+ users?

Thanks again!