DHCPCMD Converts OptionID Parameter to Octal Value

ID: Q219062

The information in this article applies to:

Microsoft Windows NT Server version 4.0

SYMPTOMS

The version of DHCPCMD available with the Windows NT 4.0 Service Pack 4 Resource Kit update has an option to set subnet option values (SetSubnetOptionValue). If you examine a DHCP server's registry, you will notice that OptionIDs contain leading 0s (zeroes). If you pass a leading 0 to DHCPCMD, it converts the optionID to an octal value and thus sets an option value that you may not have intended to set.

RESOLUTION

If, for example, you tried to set DHCP lease duration to one hour (3600 seconds) on subnet 192-168.1.1 with the following command:


DHCPCMD 192.168.1.254 SetSubnetOptionValue 192.168.1.1 051 DWORD 3600

You actually set option 041 (decimal) to a value of 3600. Option (decimal) 041 is the IP address of NIS servers on the client subnet. 3600 is not a valid value for this option.

To properly set the lease duration (or any other subnet option value), eliminate the leading 0 from OptionID on the DHCPCMD command line. In this case, the working version of the previous example would be:


DHCPCMD 192.168.1.254 SetSubnetOptionValue 192.168.1.1 51 DWORD 3600

Note also that the registry value is not a DWORD but is a binary value. Most, if not all, of the DHCP option values are stored in binary registry entries. (Strings, IP addresses, byte data, and so forth). It is possible to set many of the values by specifying DWORD as the type. If an option is of type STRING, then STRING must be specified as the type.

STATUS

Microsoft has confirmed this to be a problem in Windows NT 4.0.

Additional query words:

Keywords :
Version : winnt:4.0
Platform : winnt
Issue type : kbbug