Working with the NETSTAT Command - Page 2
The NETSTAT command even allows you to examine a single sub protocol by using the -P switch. Simply append the -P switch and the protocol name to any of the other command line switches, and the results will be based solely on the protocol that you specified. Your choices are TCP, UDP, TCPv6, UDPv6. When the -P switch is used in conjunction with the -S switch, you may also specify the IP, IPv6, ICMP, ICMPv6, TCP, TCPv6, UDP, and UDPv6 protocols.
One of the biggest concepts in TCP/IP networking is routing. NETSTAT allows you to examine a computer's routing tables by following the NETSTAT command with the -R parameter. For each active route, NETSTAT will display the destination address, the net mask, the gateway, the interface, and the metric. Beneath this information, NETSTAT will display persistent routes seperately, NETSTAT also differentiates between the routes associated with each network interface on multihomed machines.
One other noteworthy thing that NETSTAT can do is to use an interval. Earlier, we looked at using this utility to look at the number of bytes that had been sent and received. When used in this manner, you see a static display of a value that's very dynamic. Therefore, you can use the INTRAVAL switch to specify how often NETSTAT should generate a new report. When you use the INTRAVAL switch, NETSTAT will continuously loop until you press CTRL+C.
As you can see, NETSTAT is a great utility for helping you to diagnose and repair TCP/IP problems.
Brien M. Posey is an MCSE who works as a freelance writer. His past experience includes working as the director of information systems for a national chain of health care facilities and as a network engineer for the Department of Defense.