Ask Dr. Bob Your NT Questions

Q: I've heard you can use Tweak UI to set several aspects of the Windows NT 4.0 desktop. Where can I get a copy?

Tweak UI is a Windows 95 PowerToy that runs on NT and lets you adjust your user interface (UI--including menu speed, mouse sensitivity, shortcut appearance and default names, window animation and sound, icon placement on your desktop, and Internet Explorer--IE). You can download Tweak UI from http://www.microsoft.com/windows/common/a293.htm.

Q: Can you explain Point-to-Point Tunneling Protocol (PPTP)? It sounds spectacular and just might be what we need for our sales force.

Although the Internet supports user access to other computers worldwide, secure dial-up network access is still a problem. Several vendors have tried to overcome this limitation by establishing virtual dial-up standards. Examples of this class of network solutions include support for privately addressed IP, IPX, and AppleTalk dial-up over (mostly) Point-to-Point Protocol (PPP) across the existing Internet infrastructure. Specifically, virtual dial-up solutions let users access the Internet to support non-IP protocol applications in a secure manner. If you use a virtual dial-up service, different operating systems and separate protocols can share a common access Internet infrastructure that includes modems, access servers, and Integrated Services Digital Network (ISDN) routers. Most virtual networking calls are local calls for the remote user, so the costs are minimal and the session terminates locally. This type of networking can dramatically improve the phone switching capacity needed.

Vendors have taken several approaches to providing virtual network access, and not all operating systems support the necessary client or server protocols. The two most developed approaches are Cisco's Layer 2 Forwarding Protocol (L2F) and PPTP for NT. PPTP ships on the NT 4.0 Server and Workstation CD-ROMs (you apply it as a service in the Network applet of the Control Panel) and lets you establish Virtual Private Networking (VPN) access via the Internet. The most elegant aspect of these approaches is that the virtual access is platform independent--all you need is a dial-up PPP-enabled client system.

The key element to L2F and PPTP is the tunnel, a vehicle for encapsulating packets in a protocol. The tunnel has defined and understood entry and exit points on any given network. The entry and exit points are simply referred to as tunnel interfaces. In the L2F protocol, the carrier protocol is IP with User Datagram Protocol (UDP), the passenger protocol is PPP, and the encapsulator protocol is L2F. For PPTP, the carrier protocol (what Microsoft calls the control) is TCP, the passenger protocol (what Microsoft calls data packets) is PPP, and the packets are encapsulated using the Internet Generic Routing Encapsulation protocol, version 2 (GRE v2).

Because the concern here is PPTP, let's focus on how PPTP works. Each PPTP packet is either a control packet (signal or status) or a management packet (device and configuration). The packet contains an identifier, a description of length, and a magic cookie (a small string of identifying data stored on the client's Web browser). Although this approach is surprisingly simple, its design is also elegant and has significant built-in error correction and trapping. Microsoft has even accounted for collision problems: The peer with the higher IP address is always the winner.

PPTP's major selling point is its cost (it comes as part of NT 4.0). The only other cost involved is the connection fee, which is minimal for most users who connect to an Internet Service Provider (ISP) to access the Internet. If you connect to a national ISP, you can access a PPTP link in most cities for the cost of a local phone call.

Imagine that the Internet is nothing more than a large set of phone lines where you can make nearly every possible connection. PPTP works on the familiar principle of calling one phone number from another. You simply use the PPTP service to establish a VPN from one address to another.

PPTP is simple and elegant and will soon be a standard. Ascend, 3Com, Telematics, US Robotics, and Microsoft have formed a PPTP forum to establish PPTP as an open standard. At a meeting in Montreal, Quebec last June, the forum agreed on the proposed standard that will merge Microsoft's PPTP and Cisco's L2F. The merger is important because the dominant router on the Internet today is the Cisco router. You can expect to see broad acceptance of virtual Dial-Up Networking (DUN--PPTP and L2F) over the Internet in the near future. This way of connecting will be a boon to businesses that have several mobile users. The cost is low and the security is high. For more about PPTP, see Mark Minasi, "Deciphering PPTP," December 1996.

Q: I have a Practical Peripherals ProClass 288 PC Card modem. The modem appears to be working, but I keep getting a Port is busy message in Windows NT. How can I fix this?

Believe it or not, you need to boot into NT 4.0 with the RJ-11 connector pushed into the PC Card modem. After NT boots, pop out the jack and connect your phone line. I realize this procedure sounds ridiculous, but it is exactly what you need to do.

The Port is busy message is deceiving. If I set my Integrated Services Digital Network (ISDN) line speed too high in setup, I get the same message. Obviously the port is not busy, but NT is not properly returning the error.

Q: We are starting to use Systems Management Server (SMS) for network monitoring, inventorying, and upgrades. What are some general guidelines for SMS?

SMS will collect a reasonable amount of basic system information, as you see in Screen 6, and store it in a SQL Server database. Therefore, the Primary Domain Controller (PDC) for the primary SMS site (the NT server), SQL Server, and SMS all need to run optimally. To get the most out of SMS, stick to the following guidelines:

• Processor: Use at least a 133MHz Pentium for SMS and SQL Server and a symmetric multiprocessing (SMP) machine for large networks.
• Hard disk: Use separate hard disks for NT, SQL Server, and SMS. You need to configure your SMS hard disk to use NTFS. Ideally, SMS will have at least 1GB of drive space available. I generally don't put SQL Server and SMS on the same server.
• Memory: SMS and SQL Server are both memory intensive. The minimum amount of memory you need to run NT and SMS is 24MB. Even this amount is inadequate. I typically use 64MB because my computer is also the PDC.
• Network bandwidth: Obviously the bigger the bandwidth, the better the performance. This adage is definitely true on primary SMS sites. You need a minimum of switched 100Base-T for the primary site.
• SQL Server optimization: Each instance of SMS Administrator uses SQL Server. The SMS executive and hierarchy managers also use SQL Server. Because SQL Server has numerous other uses, I recommend a dual Pentium Pro with at least 128MB of memory.
• SMS load: I often see server installations running SMS and numerous other applications. A good idea is to monitor the load on your SMS and keep the SMS sites reasonably dedicated.

For more about SMS, see Spyros Sakellariadis, "SMS: Inventory Your Desktop Systems, Parts 1, 2, and 3," May, June, and July 1996.

Q: I'm considering buying one of the new 56Kbits per second (Kbps) modems. Do they work? If I buy one today, will it work in six months?

The 56Kbps standard is rapidly emerging, but so far, the computer industry has not settled on the accepted standard. The leading proponents of the new standard are Lucent, Rockwell, and US Robotics (USR). So far, about 400 companies will support K56flex, an interoperable 56Kbps modem protocol that relies on Lucent's V.flex2 and Rockwell's K56Plus 56Kbps modem technologies. Personal computer manufacturers such as AST, Compaq, HP, and Toshiba and Internet Service Providers (ISPs) and online service providers (OSPs) such as CompuServe, NETCOM, PSINet, and UUNET Technologies will support the K56flex technology. USR has about 200 ISPs committed to adopting its x2 56Kbps technology, but USR lacks strong vendor support.

Note that the Lucent/Rockwell K56flex and USR x2 standards are incompatible. The USR x2 standard peaks at 33.6Kbps on the query/upload side and approaches 56Kbps on the download side. In contrast, the K56flex standard will push high speeds in both directions. In theory, the K56flex standard lets users surf the Internet and receive online services over ordinary analog phone lines at nearly twice the speed of today's fastest modems. However, K56flex's real transmit/receive speeds will be about 40Kbps. Given the strength of support for the K56flex standard, it is undoubtedly in the strongest position to emerge as the accepted 56Kbps standard.

To achieve connect speeds of 56Kbps, you and your ISP or OSP must both have compatible 56Kbps modems. Given the rush to the Internet, this movement is occurring rapidly, but the technology is still somewhat immature. All three companies are committed to supporting a new forum-generated standard, but this standard is about a year away. User demand is causing the incompatible proposed standards to appear. I suggest you hold off for a few months to a year before buying a 56Kbps modem (for more information on the 56Kbps revolution, see "NT News Network," February 1997, and page 34). I recently faced the same dilemma and adopted Integrated Services Digital Network (ISDN).