The link below is for a very useful and
powerful network security scanner.
It has a FREE, 30-day TRIAL download period.

It you normally scan at www.pcflank.com,
do not be surprised if your scan there showed clean BUT then GFI LANGuard scan shows open ports on both TCP and UDP protocol.
Also, the "missing patch" scan is helpful as well as password weakness scans and many other network weakness detections including debug window, NET BIOS, SNMP,DNS Lookup, TRACE ROUTE, WHOIs, MS SQL audit and Scan sort capability.

I believe this software to be very complete and business-like and mostly, effective.

CLICK HERE for GFI LANGuard Network Security Scan Information and Download