Fine-tuning RAS's new features
My January article, "What's New in Windows NT 4.0 RAS?"
generated a lot of great feedback and numerous interesting questions and
problems. Many organizations use Windows NT's Remote Access Service (RAS) as the
foundation for remote access and WAN connectivity solutions. Several new
features in NT 4.0 RAS, such as Point-to-Point Tunneling Protocol (PPTP) and
Multilink RAS, turn what was once a simple remote access component into a
complex, high-powered networking solution. These new features increase the
number of problems for users implementing RAS. This article answers questions
and introduces a few new RAS-related tips and tricks. To start this discussion
of RAS, I'll answer a few questions from readers.
The Case of the Missing Subnet Mask
When I dial in to my Windows NT RAS server and obtain an IP address,
running IPCONFIG to display IP address information shows the wrong subnet mask
for the RAS adapter. This problem happens from both NT and Windows 95
clients. Why does this occur, and how can I force RAS to recognize the correct
subnet mask?
I've wondered the same thing about RAS since I started using it. We use
subnetting and variable-length subnet masks (e.g., 255.255.255.192, etc.) in my
organization, and RAS has never correctly displayed the network's subnet mask.
Instead, RAS displays the default subnet mask for the IP address. This
default address is based on the first octet of the IP address (e.g., the 192 in
the address 192.x.x.x) and determines the IP network class in use. Table 1 shows how these values are derived.
If you've noticed this behavior in RAS clients, you've probably also noticed
that RAS works fine anyway. RAS uses the default subnet mask because subnet
masks aren't a part of Point-to-Point Protocol (PPP--the industry standard
framing method RAS uses), and the system doesn't pass them over the connection.
You can stop worrying that your RAS clients are getting the wrong subnet mask:
This behavior is not unusual for RAS.
Pump Up the Volume
One thing annoys me about using Windows NT 4.0's Dial-Up Networking
(DUN): I like to hear the dialing tones and modem negotiation noises during a RAS connection (the noise reassures me that something is
happening). But something turns off my modem's speaker as soon as I hear the
dial tone (i.e., before the modem dials the phone number). Adding the string L3
in the Extra Settings field in the Advanced Connection Settings dialog box in
the Control Panel Modems applet didn't make a difference. How can I make my
modem speaker stay on during dialing and negotiation?
I have experienced this problem when manually adjusting the modem
initialization string in RAS/DUN under NT 4.0. Using the slide-tab speaker
volume adjustment in the Control Panel Modems applet is a hit-or-miss proposition.
If this adjustment doesn't work, try placing the string M1L3 in the Extra
Settings field in the Advanced Connection Setting dialog box. (To reach this
dialog box from the Modems applet, click Properties, select the Connection tab,
and click Advanced.)
If neither method works, and you're using Unimodem drivers and not the old
MODEM.INF file entries, try editing the Registry section for your modem's
Unimodem driver. To locate this entry, open one of the NT Registry editors
(REGEDIT.EXE or REGEDT32.EXE) and open the HKEY_LOCAL_MACHINE\CurrentControlSet\Control\Class key.
Under this key, you'll find a
many bizarre-looking codes (e.g., "{4D36E351...etc etc"), one of which
represents the Unimodem driver class. The specific subkey you're looking for is
{4D36E96D-E325-11CE-BFC1-08002BE10318}.
After opening this key, you'll see a subkey beginning with "0000,"
for each installed modem. Inside this key, you'll find various modem-related
sections, including one called Init.
Init has values that are the initialization strings NT uses with your
modem. You can add the M1L3 statement here or in one of the other subkeys of
this tree.
The M and L registers control modem speaker and volume settings,
respectively. Table 2 lists the possible values and definitions (I chose M1L3 to
set the volume to maximum until the modem connects; this setting is sometimes
necessary to hear a modem with a quiet speaker).
RAS Auto Redialing
I want to configure DUN as a service so that when the server boots, it
automatically dials the Internet and makes a connection, without requiring that anyone log in. I had our Windows NT 3.51 server doing this task with the command-line utility RASDIAL. When installed as a service, RASDIAL required no intervention to get the network going. Does NT 4.0 have a feature for this procedure? I don't think the RASDIAL
utility works as a service in NT 4.0.
Unfortunately, you cannot run this feature with only NT 4.0 RAS. RASDIAL
works fine with