IP Address and Subnet Mask Storage in the Windows 2000 Registry

ID: Q225060

The information in this article applies to:

Microsoft Windows 2000 Server

SUMMARY

This article describes where and how an Internet Protocol (IP) Address and a Subnet Mask are stored in the registry of a Windows 2000-based computer. Note that this article is for informational purposes and Microsoft does not recommend altering these registry settings.

MORE INFORMATION

In Windows 2000, the IP Address and Subnet Mask are stored in the following registry keys:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\ Interfaces\{Interface CLSID}\IPAddress

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\ Interfaces\{Interface CLSID}\SubnetMask

Both the IP Address and Subnet Mask are stored in Key RG_MULTI_SZ as Unicode Strings including the period character (.). Each digit's Unicode (2 byte) equivalent is stored in Low-Byte High-Byte format.

For example, 192.168.0.1 is stored as 31 00 39 00 32 00 2E 00 31 00 36 00 38 00 2E 00 30 00 2E 00 31 00 00 00 00 00.
Where
31 00 (is 0x0031 = 1)
39 00 (is 0x0039 = 9)
32 00 (is 0x0032 = 2)
2E 00 (is 0x002E = .)
31 00 (is 0x0031 = 1)
36 00 (is 0x0036 = 6)
38 00 (is 0x0038 = 8)
2E 00 (is 0x002E = .)
30 00 (is 0x0030 = 0)
2E 00 (is 0x002E = .)
31 00 (is 0x0031 = 1)
00 00 (is 0x0000 = NULL)
00 00 (is 0x0000 = NULL)

If the interface is logically multihomed, then the next IP Address is stored after the previous address in the same format.

Similarly, the Subnet Mask of 255.255.255.0 is stored as 32 00 35 00 35 00 2E 00 32 00 35 00 35 00 2E 00 32 00 35 00 35 00 2E 00 30 00 00 00 00 00
Where
32 00 (is 0x0032 = 2)
35 00 (is 0x0035 = 5)
35 00 (is 0x0035 = 5)
2E 00 (is 0x002E = .)
32 00 (is 0x0032 = 2)
35 00 (is 0x0035 = 5)
35 00 (is 0x0035 = 5)
2E 00 (is 0x002E = .)
32 00 (is 0x0032 = 2)
35 00 (is 0x0035 = 5)
35 00 (is 0x0035 = 5)
2E 00 (is 0x002E = .)
30 00 (is 0x0030 = 0)
00 00 (is 0x0000 = NULL)
00 00 (is 0x0000 = NULL)

If the interface is logically multihomed, then the corresponding Subnet Mask to the next IP Address is stored after the previous mask in the same format.

Additional query words: 2000

Keywords : kbenv kbnetwork
Version : WINDOWS:2000
Platform : WINDOWS
Issue type : kbinfo