MS Proxy Secure?

[mdavis <mdavis () telekbird com cn>]

Hi,everybody,

Do me a favour.Who can tell me if my LAN is secure enough?My LAN consist of 
more than 15 NT server.Between the LAN and Internet I placed a MS Proxy server
2.0,no other Firewall software installed.I enabled Proxy packet filtering and 
access control and other feature.Do you think it's a bad idea?I need a 
Firewall installed?Any advice appreciated greatly.

Sincerely
sam
mdavis () telekbird com cn