The TCP/IP Guide - TCP/IP Configuration Utilities (ipconfig, winipcfg and ifconfig)

Windows takes a somewhat different approach to network configuration than UNIX. As we have seen, the UNIX ifconfig program can be used both to view and modify a wide range of configuration parameters. In Windows, however, most setup and parameter modification is done using the Windows Control Panel. Windows does include a utility that is somewhat similar to UNIX’s ifconfig, but it has far less functionality, and is used mainly to inspect the existing configuration, not change it. It also allows an administrator to easily perform a few simple functions on a host.

On most newer versions of Windows, the equivalent of ifconfig is a command-line utility called ipconfig. Like ifconfig, the Windows utility is controlled using options that are supplied to the program. However, because it is so much simpler than ifconfig, there are only a few different options that can be used. These are summarized in Table 308.

**Table 308: Typical Windows *ipconfig* Options and Parameters**
Option / Parameters	Description
*(none)*	When called with no options or parameters, ipconfig displays the IP address, subnet mask and default gateway for each interface on the host.
*/all*	Similar to calling ipconfig with no options, but displays more detailed configuration information about the host’s interfaces.
*/release [<adapter>]*	Releases (terminates) the DHCP lease on either the specified adapter (interface), or all interfaces if none is provided.
*/renew [<adapter>]*	Manually renews the DHCP lease for either the specified adapter (interface), or all adapters if none is mentioned.
*/displaydns*	Displays the contents of the host’s DNS resolver cache.
*/flushdns*	Clears the host’s DNS resolver cache.
*/registerdns*	Refreshes (renews) all DHCP leases and also re-registers any DNS names associated with the host.
*/showclassid <adapter>*	Displays DHCP class IDs associated with this adapter (these are used to arrange clients into groups that are given different treatment by DHCP servers.) The adapter must be specified, even if there is only one.
*/setclassid <adapter> [<classid>]*	Modifies the DHCP class ID for the specified adapter.

As mentioned earlier, ipconfig is most often used to just examine the existing configuration. When simplified information is needed it is called with no options; an example of the output from this use of the command is shown in Table 309. For detailed information on interfaces, the “/all” option is used; an example is in Table 310 (slightly modified so it is easier to read).