RRAS PPP Connections May Time-out on Slow or Delayed Links

• Microsoft Windows NT Server version 4.0
• Microsoft Routing & Remote Access Service Update for Windows NT Server version 4.0

SYMPTOMS

If you have Routing and Remote Access Service (RRAS) installed on a computer running Windows NT Server and you attempt to dial out to establish a PPP connection with a remote RAS server, the PPP connection may not successfully complete at times. The inability to connect is most likely to occur on a slow or delayed link in which the round-trip delay for a PPP negotiation packet is approximately 1 second or greater. Also, the following error message may be displayed in the graphical user interface of the dialing computer:

Error 718 - Timeout while waiting for valid response from remote peer.

CAUSE

The initial phases of starting a PPP link involve negotiating the Link Control Protocol (LCP) layer of the connection. LCP itself has a time-out function when waiting for a response to a configuration request from its PPP peer. If the sending side does not receive a configuration acknowledgement in time (that is, in less than 1 second), then the sending side times out and sends a second configuration request. In the meantime, the receiving end of the PPP connection receives a second configuration request, which results in a restart of LCP and the timeout counter is reset to zero. This scenario repeats in a "round-robin" fashion between the two PPP peers. The ultimate result is that negotiation of the LCP layer never completes.

RESOLUTION

To resolve this problem, obtain the latest service pack for Windows NT 4.0. For additional information, please see the following article in the Microsoft Knowledge Base:

Q152734 How to Obtain the Latest Windows NT 4.0 Service Pack

STATUS

Microsoft has confirmed this to be a problem in Windows NT 4.0. This problem was first corrected in Windows NT 4.0 Service Pack 5.

Additional query words:

Keywords : nt4sp5fix
Version : winnt:4.0
Platform : winnt
Issue type : kbbug