With all the shouting about Process Explorer 11.0, it would be unfair to not talk about TCPView 2.51, an improved network monitoring utility from Sysinternals that Mark Russinovich released rather quietly, back in August.
TCPView lists all of the currently-active network endpoints in a system and lets you sort them by process name, protocol, local address and remote address, and state ("Listening" / "Established" / etc.). The display updates once a second by default, but this can be changed to two seconds, five seconds or on-demand as needed (from the View | Update Speed menu).
Any changes that take place to network connections are indicated in color. A change in state is shown in yellow; a closed connection, in red; new connections, in green. Both IPv4 and IPv6 connections are shown; the Protocol column will let you know which version is being used for a given connection. The program can also optionally show connections without endpoints.
Aside from just displaying existing connections, TCPView also lets you derive extended information about the processes responsible for them and manually close connections or kill processes from within the program. You can run a quick whois lookup on a given hostname and copy the contents of selected rows in the display to the clipboard as tab-delimited text. The program also has a console-only version (TCPVCon), with command-line options that let you immediately export the program's output to CSV -- essentially the same output as Netstat.
Note that in Windows Vista, unless you run the program as Administrator, some options may not work correctly. For instance, if you attempt to obtain the properties of a system service that is creating a network connection, you'll get an error unless you're running in Admin mode.
About the author: Serdar Yegulalp is editor of Windows Insight (formerly the Windows Power Users Newsletter), a blog site devoted to hints, tips, tricks and news for users and administrators of Windows NT, Windows 2000, Windows XP, Windows Server 2003 and Vista. He has more than 12 years of experience working with Windows, and contributes regularly to SearchWinComputing.com and other TechTarget sites.
This was first published in September 2007