firewall test

[Robert Williams]

I have a server firewall we developed using RHL Fedora Core 3.  It protects
our servers and also itself (since the server also serves as a PHP web
server).  Our workstations are on a separate network, and I wanted to know
what port scanner software (free, and windows application) or tests I can do
to ensure the firewall is indeed protecting our servers from DoS and
whatnot.  

 
Robert Williams
Programmer / Web Developer / Network Administrator
Covenant Data Systems, Inc.
http://www.covenantdata.com
rwilliams at covenantdata.com