This section provides an overview of common security tools.
The GNU/GPL tool Network Mapper (Nmap) from http://insecure.org is one of the best security tools available today. It can operate on a single machine or on a very large network. It discovers what services are running and what operating system is being used. It also reveals a lot about a firewall or packet filters in place. In essence, it's very effective in mapping your network.
You should become familiar with this tool and learn to use it.
Never scan networks you do not own or have permission to scan. It can be considered a hostile act. In other words, use this tool for your administrative purposes only, and do not use it to hack or attack any other networks or servers.
After you install Nmap on Windows machines, it runs via the graphical user interface (GUI). To begin using Nmap, enter your host name or IP address in the Target box. Next, select the type of scan from the Profile drop-down.
Using the drop-down box in the GUI, you may select from among popular combinations of scanning. These preconfigured options are only a handful of the many combinations. They represent many of the normal commands you'll use. When you make a selection, a command is entered in the Command box. For example, if you select the Intense Scan option, the following command is entered:
nmap -sS -sU -T4 -A -v -PE -PS22,25,80 ...