When initially configured, a Windows 2000 RAS server supports 1000 PPTP (Point-to-Point Tunneling Protocol) and 1000 L2TP (Layer 2 Tunneling Protocol) connections.
If you use the Routing and Remote Access snap-in, in the Administrative Tools folder, you can change these Ports to support 16,383 PPTP and 30,000 L2TP connections. You then have to shutdown and restart your RAS server for the changes to become effective.
To increase the limits beyond those supported by the GUI, use Regedt32 to navigate to:
Expand each numbered sub-key, looking for the DriverDesc value name whose data value is WAN Miniport (L2TP). The MaxWanEndPoints value name of that sub-key contains the current maximum. Double-click the MaxWanEndPoints value name and select the Decimal radix. Type the L2TP maximum that you wish to set and press OK.
Repeat these steps for PPTP, by locating the sub-key whose DriverDesc value name has a data value of WAN Miniport (PPTP).
Exit Regedt32, shutdown and restart your RAS server.
NOTE: The next time you look at Ports Properties in the Routing and Remote Access snap-in, you will see these new values.