PRB: RasDial() Takes Longer to Dial Out

• Microsoft Win32 Software Development Kit (SDK), versions 3.5, 3.51

SYMPTOMS

RasDial() takes more time to dial and authenticate a RAS (remote access server) user if the RAS server being dialed is using older RAS protocols and if the application is not using a phone book entry while calling RasDial().

CAUSE

Windows NT versions 3.5 and 3.51 use PPP (point-to-point protocol) as the default protocol for dialing out. However, older versions of RAS servers namely, RAS servers for Windows NT version 3.1 and point-to-point servers for Windows for Workgroups do not implement the PPP protocol.

When an application calls RasDial() without specifying a phonebook entry, RasDial() uses the default phonebook entry settings. The default framing protocol for Windows NT versions 3.5 and 3.51 is PPP, so that is tried first. If PPP doesn't work, the old RAS framing protocol is tried. The failed attempt to connect with PPP accounts for the delay.

When a user creates a phonebook entry and dials an older RAS server, RAS on the Windows NT client tries PPP as the framing protocol, which eventually times out, and RAS falls back to old RAS protocol. RasDial() marks the phonebook entry so that the next time it is dialed old RAS protocol is tried first with fallback to PPP. Thus, the user sees the same delay on the first call, but all subsequent calls are quick.

RESOLUTION

Application programmers can create an entry with RASPHONE and override the phone number at dial time, thus using the entry as a template with options appropriate for the down-level server. If it is known that the server is an older RAS server and will not be upgraded, you can clear all three check boxes for all three protocols. Using RASPHONE, on the Edit menu, click Network, and then clear the check boxes in the PPP group. This trick forces old RAS protocol and eliminates the training call.

STATUS

This behavior is by design.

Keywords : kbnetwork kbAPI kbNTOS350 kbNTOS351 kbRAS kbSDKPlatform kbGrpNet
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Issue type : kbprb