Netsh is a powerful and indispensible command-line tool for updating Windows network configuration settings. However, the variety of options available with Netsh can make it confusing to work with. In this column, I'll show you ten ready-to-use examples of Netsh commands for some of the most widely used network functions. For more information about Netsh, you can download "Windows Server 2008 Network Shell (Netsh) Technical Reference"from the Microsoft Download Center.

 

10. Show the system's current IP configuration—You can use the following command to see if the system is using DHCP or static addressing as well as to show the system's current IP address, submask, gateway address, and DNS server:

netsh interface ip show config

9. Configure a remote system—One of the best features of the Netsh command is its ability to work with remote systems as easily as it can local systems. The set machine command changes the computer that the Netsh command operates on to a different system on the network. For this command to work, you need to be logged on with an account that has administrative rights on the remote system:

netsh set machine win2008-2

8. Working with IPv6—Netsh commands work with both Windows IPv4 and IPv6 network stacks. To display your system's IPv6 address, use the following Netsh command:

netsh interface ipv6 show address

7. Enable and disable Windows Firewall—Netsh can work with the built-in Windows Firewall. With the release of Windows Server 2008, the older Netsh firewall commands have been deprecated and replaced by the advfirewall commands. The following commands show how to disable then re-enable the Windows Firewall:

netsh advfirewall set currentprofile state off
netsh advfirewall set currentprofile state on

6. Open a firewall port—You can also use Netsh to open ports in the firewall for various applications. The following example shows how to open TCP port 1434 for Microsoft SQL Server access:

netsh advfirewall firewall
  add rule name="SQL Server"
  dir=in action=allow
  protocol=TCP localport=1434

5. Display network adapters and their status—Many of the Netsh configuration commands require you to supply the name of the interface that you want to configure. The default value is usually Local Area Connection, but many administrators and users change this value. To find the name of the system's network adapters or a system's wireless network adapters, use the following commands:

netsh interface show interface
netsh wlan show interface

4. Configure a network adapter to use a static IP address—The following example shows how you use Netsh to set the IP address of the network adapter named Local Area Connection to 192.168.0.100, the subnet mask to 255.255.255.0, and the gateway address to 192.168.0.254:

netsh interface ip
  set address "Local Area Connection"
  static 192.168.0.100
  255.255.255.0 192.168.0.254 1

3. Configure a network adapter with the address of a DNS server—When you change the system's IP address type to static, you typically need to change the DNS configuration as well. This example shows how you use Netsh to configure the Local Area Connection to use a DNS server with the address 192.168.0.2:

netsh interface ip
  set dns "Local Area Connection"
  static 192.168.0.2

2. Add a second DNS server to a network adapter's configuration—Many networks use multiple DNS servers. To add a secondary DNS server with the address 192.168.0.3, use the following command:

netsh interface ip
  add dnsserver "Local Area Connection"
  192.168.0.3

1. Set a network adapter to use a DHCP-assigned IP address—You can also use Netsh to set your system's network adapter to use a DHCP server for its IP address and to dynamically obtain the address of your network's DNS servers. The following Netsh command configures your network adapter to use DHCP and DNS:

netsh interface ip
 set dns "Local Area Connection" dhcp


Wireless LAN (WLAN) Commands

One new feature of Windows 7 and Windows Server 2008 R2 is Wireless Hosted Networks. It lets you create a virtual wireless access point (AP) with your wireless adapter, even when connected to a wireless network. Once you enable Internet Connection Sharing (ICS), others can connect to your virtual AP with the encryption key and access the Internet.

You can create and manage Wireless Hosted Networks with Netsh:

Windows Networking
Figure 1: Setting up and starting a Wireless Hosted Network.

Here are some new WLAN commands to show or print the value of other settings:

Here are a couple more new miscellaneous Netsh WLAN commands:

Local Area Network (LAN) Commands

There are only two new Netsh LAN commands, which are the wired version of the two new Netsh WLAN commands:

Windows Filtering Platform (WFP) Commands

The Windows Filtering Platform (WFP) is a new architecture that debuted in Windows Vista and Windows Server 2008. It gives software developers much more access and control over the TCP/IP stack.

Microsoft added a diagnostic tool for the WFP in Windows 7 and Windows Server 2008 R2. It can help you troubleshoot issues with Windows Firewall and IPsec. It runs diagnostic tests and creates a report in XML format. Here are the diagnostic capture commands:

Start Windows Capture
Figure 2: Starting and stopping the capturing.

Two persistent options for the diagnostic capturing can be set with the netsh wfp set options command, using the following parameters:

Network Trace Commands

Netsh in Windows 7 and Windows Server 2008 R2 features trace commands to help you diagnose and trace network-related issues. Here are three commands you need to know to use the diagnosis tool:

Save Session Trace
Figure 3: Running a FileSharing diagnosis to see why the LAPTOP computer isn’t accessible.

Here are the commands to perform network traces:

Stop/Start Trace
Figure 4: Starting and stopping a trace on the WLAN.

The trace convert and trace correlate commands can help you manipulate the trace files. Plus you might look into the following that can display more information related to tracing and diagnosis: