Firewall for NT networks with transparent authentication

[Per-Henning Valderhaug <valper @ nodeca . mil . no>]

Hi all!

I need a firewall that is able to transparently authenticate the users
placed at the inside of the firewall (in the LAN).
Inside users should be granted access to spesific external hosts based upon
their username in the Windows NT network. 
Any such products out there? What would you recommend?

Best regards
Per-Henning
         __________________________________
       | Per-Henning Valderhaug            |       
       | Forsvarets Tele- og Datatjeneste  |       
       | Oslo mil/Akershus                 |       
       | N-0015 OSLO                       |       
       | NORWAY                            |       
       |                                   |       
       | Phone:        +47 22 40 24 00     |
       | Direct line:  +47 22 40 26 88     |
       | Telefax:      +47 22 40 29 97     |
      /)                                   (\      
     / ) e-mail:       valper @
 nodeca .
 mil .
 no( \    
   _( (|___________________________________) )  />  
  (((\ \)  / )                       / )  / //))/  
  (\\\\ \_/ /                        \ \_/ /////    
   \       /                          \       /      
    \    _/                            \_    /          
- ----/   /--------------------------------\   \----
   /   /                                  \   \