mpearl11
08-16-2003, 01:51 AM
Windows XP uses Automatic Private IP Addressing (APIPA) to automate Internet Protocol (IP) configuration of network connections.
By default, the computer first tries to contact a DHCP server on the network and dynamically obtain configuration for each installed network connection, as follows:
If a DHCP server is reached and leased configuration is successful, TCP/IP configuration is completed.
If a DHCP server is not reached after approximately 60 seconds or leased configuration fails, the computer uses the setting on the Alternate Configuration tab to determine whether to use APIPA for automatic TCP/IP configuration or to configure TCP/IP with the alternate configuration. When APIPA is used, Windows XP uses an address in the APIPA IP address range (169.254.0.1 through 169.254.255.254) and the subnet mask is set to 255.255.0.0.
The range of IP addresses (from 169.254.0.1 through 169.254.255.254) used for APIPA is reserved by the Internet Assigned Numbers Authority (IANA). Any IP addresses within this range are not used on the Internet.
This allows several computers, using TCP/IP to connect to one another with the use of a hub or switch, without DHCP services available. You can, however,disable this APIPA feature if you like. To do this:
In Registry Editor, navigate to the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Tcpip\Parameters\Interfaces\adapter_name
On the Edit menu, point to New, and then click DWORD value.
Create the following entry:
IPAutoconfigurationEnabled: REG_DWORD
Assign a value of 0 to disable Automatic Private IP Addressing (APIPA) support for the selected network adapter. If the IPAutoconfigurationEnabled REG_DWRORD is not present, it's default of 1 is assumed.
By default, the computer first tries to contact a DHCP server on the network and dynamically obtain configuration for each installed network connection, as follows:
If a DHCP server is reached and leased configuration is successful, TCP/IP configuration is completed.
If a DHCP server is not reached after approximately 60 seconds or leased configuration fails, the computer uses the setting on the Alternate Configuration tab to determine whether to use APIPA for automatic TCP/IP configuration or to configure TCP/IP with the alternate configuration. When APIPA is used, Windows XP uses an address in the APIPA IP address range (169.254.0.1 through 169.254.255.254) and the subnet mask is set to 255.255.0.0.
The range of IP addresses (from 169.254.0.1 through 169.254.255.254) used for APIPA is reserved by the Internet Assigned Numbers Authority (IANA). Any IP addresses within this range are not used on the Internet.
This allows several computers, using TCP/IP to connect to one another with the use of a hub or switch, without DHCP services available. You can, however,disable this APIPA feature if you like. To do this:
In Registry Editor, navigate to the following registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\Tcpip\Parameters\Interfaces\adapter_name
On the Edit menu, point to New, and then click DWORD value.
Create the following entry:
IPAutoconfigurationEnabled: REG_DWORD
Assign a value of 0 to disable Automatic Private IP Addressing (APIPA) support for the selected network adapter. If the IPAutoconfigurationEnabled REG_DWRORD is not present, it's default of 1 is assumed.