Diagnosing Connectivity Issues With NETSH

With each new version of Windows, Microsoft has included more advanced diagnostic software. Windows.NET is no exception. The NETSH utility provides a wide variety of network related diagnostics. In this article, Ill examine one particular area of the NETSH command; the DIAG option.You can access the NETSH utility by opening a Command Prompt window and entering the NETSH command. When you do, the usual command prompt will turn to the NETSH prompt. Next, enter diagnostic mode by entering the DIAG command. When you do, the NETSH prompt will change to NETSH DIAG.Once you have reached the NETSH DIAG prompt, there are several things that you can do. Below Ive listed a summary of the commands that you can enter and what those commands do.CONNECTLike most of the other available commands, the connect command has several available options. The commands general purpose is to test various types of connections, such as the connection to a mail server or to a Proxy Server. Below is a summary of the various command optionsCONNECT IEPROXY tests the connection to the Proxy ServerCONNECT MAIL tests the connection to the default mail server as defined through Outlook or Outlook ExpressCONNECT NEWS - tests the connection to the default NNTP server as defined by Outlook or Outlook Express.The Connect command also has an option to test the connection to a Web Server. However, you must specify the IPHOST parameter followed by the URL and port number. An example of the syntax is:CONNECT IPHOST www.brienposey.com 80GUIAnother command that you can use is GUI. Entering the GUI command at the NETSH DIAG prompt will cause Windows to open Internet Explorer with a diagnostic Web page. This page allows you to perform a thorough scan of your systems networking components. When complete, the scan will display a report detailing your network configuration, each test run, and the results of the test.HELPThe Help command displays a help screen detailing all of the available commands. The help screen is presented in two different sections. The top section lists commands that are available from the NETSH prompt. The bottom half lists commands available from the NETSH DIAG prompt.PINGThe PING command works similarly to the normal TCP/IP command except that rather than specifying an IP address or a DNS name, you specify the name of the device that you want to PING. For example, the PING DNS command pings all of the systems DNS servers, while the PING MAIL command pings the default mail server as defined by Outlook or Outlook Express. Below is a summary of the options available with the PING command:ping adapter - Ping all of the Adapters.ping dhcp - Ping the DHCP servers for each Adapter.ping dns - Ping the DNS servers for each adapter.ping gateway - Ping the default gateway servers for each adapter.ping ieproxy - Ping Internet Explorer's proxy.ping ip - Ping all IP addresses for each Adapter.ping iphost - Ping an IP address or host name.ping loopback - Ping loopback (127.0.0.1).ping mail - Ping Outlook Express mail server.ping news - Ping the news server.ping wins - Ping the primary and secondary WINS servers for each AdapterSHOWThe SHOW command is used to display detailed information regarding some aspect of your network. For example, the SHOW ADAPTER command displays a list of all of the network adapters in the system. Likewise, the SHOW CLIENT command displays a list of the clients that the system is configured to accept (Windows network, terminal service, Web clients, etc.). You can see a summary of al of the SHOW commands below.show adapter - Displays all of the Adapters.show all - Displays all categories.show client - Displays all network clients.show computer - Displays computer information.show dhcp - Displays the DHCP servers for each adapter.show dns - Displays the DNS servers for each adapter.show gateway - Displays the default gateway servers for each adapter.show ieproxy - Displays Internet Explorer's server name and port number.show ip - Displays the IP address for each adapter.show mail - Displays the mail server name and port number.show modem - Displays all modems.show news - Displays the news server name and port number.show os - Displays operating system information.show test - Displays all categories and performs all tests.show version - Displays the Windows and WMI version.show wins - Displays the primary and secondary WINS servers for each adapter