Network security is not just about implementing a firewall and then leaving it alone. You should be auditing, reviewing logs, running scans, and developing good security policies that will keep your network protected. This article will show you some tools that can help you manage network security in a Windows network.
Port scanners
A port scanner will probe your system for open TCP and UDP ports. This is a good tool to help you determine what ports you may or may not need to keep open on your firewall and routers. It will also help you determine whether you have any active Trojans (placed by hackers) on your system that are listening on open ports. Here are two port scanners that will help you identify open ports on your systems.
SuperScan
SuperScan is a free download that allows you to check a range of ports or to scan a range of IP addresses. It comes with a slick and easy to use GUI, as shown in Figure A.
Figure A
FScan
FScan is a command-line port scanner (Figure B) that allows you to scan ports and redirect the results to a text file of your choice. In addition to scanning TCP ports, you can scan UDP ports. This tool can scan over 200 ports per second. To download FScan, click here and then click Scanner, FScan, and Download Now.
Figure B
TCP/IP tools in Windows
When administering security, you need to have a good grasp of the basic TCP/IP tools. The following are command-line TCP/IP tools that are built in to Windows NT/2000:
Netstatâ€" Windows administrators should be very familiar with this tool. It can quickly tell you what TCP and UDP ports are in use on a system. From the command line, simply type netstat -a for a list of open and listening ports, such as the one shown in
Figure C
Ipconfigâ€" This utility displays the TCP/IP configuration of your computer. Type ipconfig /all, as shown in Figure D, to display the TCP/IP configuration.
Figure D
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You missed the best security scanner!
Most in the security industry agree that the open source Nessus (www.nessus.org) is the best thing around with respect to security probing of hosts. It runs on Linux etc. but can scan Windows hosts.