WinNT Systems Running RAS May Exhaust Available DHCP Leases

• Microsoft Windows NT Workstation version 4.0
• Microsoft Windows NT Server version 4.0

SYMPTOMS

A RAS service configured to use dynamic host configuration protocol (DHCP) to allocate IP addresses for dial-up clients may acquire more IP address leases than needed, thereby depleting available addresses.

The leased addresses are indicated by a telephone icon in the Active Leases window of DHCP Manager.

This problem can occur when laptop users on the network who have installed RAS and configured it for dialing out and receiving calls start their systems on and off the network.

CAUSE

During initialization, the RAS service acquires new leases because it fails to read information regarding previously acquired leases. The previously leased addresses, now orphaned, will only be returned to the pool of available addresses when their leases expire.

RESOLUTION

Obtain the following fix or wait for the next Windows NT service pack.

This fix should have the following timestamp:

   12/05/97  03:14p                28,432 Rasiphlp.dll (i386 platform)

   12/05/97  03:12p                46,864 Rasiphlp.dll (Alpha platform)

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 4.0. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.