Gsheild 2.8 how-to guide?

[Black, Jonathan]

Help, We are using Gshield 2.8 along with Squid 2 and I need to better
understand how Gshield works. The Linux box was setup years ago and the
original admin has left us with no documentation.
 
We just purchased a Barracuda Spam 300 box to help control our email issues
but when we install it inside the firewall it cannot reach the outside
world. Ping and http do not seem to find the internet but work on any system
inside the firewall. This puts a big cramp in our plan.
 
The Linux box is the gateway device and passes the mail to an internal
MSExch 5.5 box. We wanted to have the mail redirect through the gateway to
the Cuda and then filter the results to Exchange and then have outbound go
straight out the gateway. Cuda does not have any techs with Gshield or Squid
experiance and I have reached the limit of my knowledge. 
 
Any help on this configuration would be appreciated or a pointer to a good
reference book?
 
Jonathan A Black
Data Processing Administrator
Syncom Pharmaceuticals 
973-822-9222 x 1126
800-400-0056 x 1126
862-432-6992 mobile