Nmap

I voted for Nmap ;)

difficiel to choose as I know very less of them
 

I did only use sometimes wireshark or nmap and so I've choosen whireshark. I know its not the best. And I know that you can not really decide what is better because I've used nmap more often but whireshark in special cases.

The software should be separated into network categories.

While Wireshark and other packet sniffing programs are handy they are not really security. However iptables is the core component of ufw/gufw and is desperately needed by anyone online these days.

Whoa! This is really a tough one. Bro-ids is a great nid. ClamAV is a great AV and pares down the deluge of virii besotting our inboxes on more mta's than the commercial competitors would like to admit. Nessus _was_ a great network protocol analyzer before it's developer got bit by the greed bug so it's out of the running. The good news being that Wireshark, now arguably the best protocol analyzer, was born and kicked it's arse. Before any of the above were even twinkles in their developers eyes', nmap was the cat's meow, and continues to rock it today. Not to mention the venerable tcpdump. Quite the potpourri of disparate tools here! Hmmm.... decisions, decisions.... Think I'll go with nmap on this one. Or maybe Wireshark. Guess I'm going to have to flip a coin; head's nmap, tails Wireshark. Heads it is :)