Windows 7 / Networking

---

IPConfig

IPConfig (Ipconfig.exe) is a useful command-line tool for troubleshooting problems with automatic configuration such as Dynamic Host Configuration Protocol (DHCP). You can use IPConfig to display the current IP configuration, identify whether DHCP or Automatic Private IP Addressing (APIPA) is being used, and release and renew an automatic IP configuration.

To view detailed IP configuration information, open a command prompt and run the following command.

ipconfig /all

This command displays the current IP configuration and produces output.

To determine whether DHCP addressing was successful, open a command prompt and run the following command.

ipconfig

This command produces output similar to the following.

Windows IP Configuration

Ethernet adapter Local Area Connection:

 Connection-specific DNS Suffix .  :
 Link-local IPv6 Address	   : fe80::9477:c944:e7dc:bb4f%14
 Autoconfiguration IP Address. . . : 172.16.0.24
 Subnet Mask . . . . . . . . . . . : 255.255.0.0
 Default Gateway . . . . . . . . . : 172.16.0.1

If the IP address shown is in the range from 169.254.0.0 through 169.254.255.255, Windows used APIPA because the operating system was unable to retrieve an IP configuration from a DHCP server upon startup, and there was no alternate configuration. To confirm this, examine the IPConfig output for the DHCP Enabled setting without a DHCP server address.

To release and renew a DHCP-assigned IPv4 address, open a command prompt with administrative credentials and run the following commands.

ipconfig /release
ipconfig /renew

Windows will stop using the current IPv4 address and attempt to contact a DHCP server for a new IPv4 address. If a DHCP server is not available, Windows will either use the alternate configuration or automatically assign an APIPA address in the range of 169.254.0.0 through 169.254.255.255.

To release and renew an automatically assigned IPv6 address, open a command prompt and run the following commands.

ipconfig /release6
ipconfig /renew6