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a network. The acronym NDS was later changed to Novell Directory Services. NDS provides a database of all network objects or resources. Figure 4.1 shows an NDS tree. The key point to remember here is that NDS is a network-based service. Notice that the NDS tree treats print devices, disk volumes, users, and groups as leaf objects, or resources, in the tree. Earlier versions of NetWare used bindery services; the bindery kept track of resources on a server-by-server basis.

FIGURE 4.1 A typical NDS tree structure

Chapter 5, “Implementing and Maintaining a Secure Network,” examines NDS and eDirectory.

In the most recent versions of NetWare, NDS has been expanded and renamed eDirectory. Novell changed the environment so that it now operates using TCP/IP as the native network protocol.

Novell also provides a number of applications, tools, and products that compare favorably to other network-based products. Two of the more popular Novell products are GroupWise, an e-mail and collaboration system similar to Microsoft Exchange, and a software and configuration distribution product known as ZENworks.

The last version of NetWare to be released was 6.5. All versions above 5.0 use TCP/IP as their default networking protocol rather than IPX/SPX. Novell is now in the process of converting its products to Linux (which has always used TCP/IP as the default). Open Enterprise Server (OES) is a shell that runs on top of NetWare or Linux and allows Novell’s remaining proprietary tools to run on both operating systems.

Microsoft Protocols

Microsoft and IBM were early leaders in PC network technologies. Early PC systems supported a rudimentary peer-to-peer networking environment that was fast and required little overhead. Of course, networks in those days were simple, and high levels of functionality weren’t expected. The two original network protocols available for PCs were NetBIOS and NetBEUI.

The following sections include brief discussions of each of these protocols, plus Windows Internet Naming Service (WINS). Although WINS isn’t technically a protocol, it’s an integral part of the traffic on a Microsoft network.

Over the years, Microsoft has introduced a number of other protocols and services to facilitate communication among Windows network systems. Microsoft has stated that future network products will utilize TCP/IP, which is now replacing most of these protocols.

NetBIOS

Network Basic Input Output System (NetBIOS) is the native protocol of Windows PCs. NetBIOS provides a 15-character naming convention for resources on the network. It’s a broadcast-oriented network protocol in that all traffic is available to all devices in a LAN. The protocol can be transported over NetBEUI, TCP/IP, or IPX/SPX.

The biggest vulnerability with NetBIOS is that it opens ports for file and print sharing. These ports (which can include 135 through 139 and 445) can be accessed across the Internet as well as by devices on the local LAN.

NetBEUI

The NetBIOS Extended User Interface (NetBEUI) is used to transport NetBIOS traffic in a LAN. NetBEUI and NetBIOS were originally packaged as a single product, beginning with the release of Windows for Workgroups. As network technologies advanced, NetBIOS was turned into a separate protocol. Figure 4.2 shows a network running only NetBEUI.

FIGURE 4.2 NetBEUI network using a VPN over a TCP/IP network

NetBEUI is a nonroutable protocol, meaning that it can’t be sent across routers. NetBEUI traffic is easy to intercept internally using a network sniffer.

WINS Service

The Windows Internet Naming Service (WINS) translates NetBIOS names to TCP/IP addresses. WINS runs as a service on a server. It provides name translation for networks, similar in nature to DNS. If WINS isn’t available, a Windows system can use a local file, LMHOSTS, to resolve NetBIOS names to TCP/IP addresses. In Figure 4.3, a WINS server provides a NetBIOS name to TCP/IP addresses in a LAN. This resolution process has been coupled by DNS with Windows Server products.

FIGURE 4.3 WINS Server