A+ Certification / Beginners


The netstat command line utility is used to troubleshoot TCP/IP connections. If you type the netstat command by itself, it displays a list of connections that your system has with remote systems and the associated ports.

Like nbtstat, netstat supports a number of switches to help you get the most information possible out of the command. Table below lists some of the more popular netstat switches.

NETSTAT Switches
/?Shows a list of switches supported by netstat and a brief description of each switch.
/aUsing the -a switch displays all connections that your system has but also all listening ports. A port is what an application uses as an endpoint of communication. For example, applications such as Internet Explorer use a port, and that port is where a Web server sends the data so that the data reaches Internet Explorer.
/oDisplays the process ID of the application that has opened the port. You can use this information with Task Manager to track down the application that opened the port.
-A <ip address>Shows the connections for the protocol provided to the switch. For example, you could type netstat -p TCP to view all the TCP connections. In this example, you will not see the UDP connections.

An example usage of the netstat command is as follows:

netstat -a -o


pathping is a newer command line utility to the Windows world that allows you to ping a destination, but like the tracert command, you get a list of hops (routers) from the source to the destination. After the list of hops is determined, pathping sends a number of messages to each hop to calculate statistics on each hop, such as the number of lost packets.


nslookup is a TCP/IP utility used to query DNS and to troubleshoot problems associated with DNS. With nslookup, you can query for a specific type of record, such as e-mail server records (known as MX records) if you want to know the mail servers for a particular company.

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