Once you install SP1 (Service Pack 1), or later, to Windows Server 2003, you can set all the automatic configuration and proxy settings of your connections that are blank, or that are not set, to be the same as the LAN settings:
1. Open a CMD.EXE window on the server, or on any networked computer that has REG.EXE installed.
2. Type the following command and press Enter:
REG ADD "\[\\ComputerName\\]HKLM\Software\Microsoft\Windows\CurrentVersion\Internet Settings" /V DialupUseLanSettings /T REG_DWORD /F /D 1
Where \[\\ComputerName\\] is optional and points to a remote Windows Server 2003 with at least SP1 installed.