What is the latest and greatest port scanning software?

What is it?

Thanks.

Windows, Mac or Linux? Open Source or Commercial?

I only ask because there are different port scanning software for different applications. most of the commercial apps run at roughly $10,000 per license which happen to be tied to NSA Vulnerability databases. Which tend to be the most accurate and up-to-date. and others Open Source which can have a weeks delay in the vulnerabilities over the paid for software.

Snort is a great scanner and can also be configured to act as an Intrusion Detection System. And runs on all flavors of Operating Systems.

for Linux you can use snort or another powerful utility called nmap. once installed a simple command ie.. nmap -sS "ip address or address range" and it will scan all the ports on the network and return simple stats of the ports. It can get a lot more advanced and even use scripts that will scan for specific traffic including virus traffic like the zero day worm.

All in all it really comes down to what is your budget?

Need more info on what you are trying to do.