4.5. Identifying Common Network Problems
A client server environment cannot be all things to all people; each type of client server environment has its strengths and its weaknesses. It's important that you understand what to look for when troubleshooting the most common client server environments. This will help you identify and fix problems more accurately and therefore more quickly, enabling a user to remain productive.
4.5.1. Critical Information
Given a troubleshooting scenario between a client and the following server environments, you should be able to identify the cause of a stated problem.
4.5.1.1. Unix/Linux/Mac OS X Server
As we discussed in Chapter 3, Unix is a flexible operating system that is mostly command line driven. Linux is a spinoff from Unix that provides some GUI capability. Mac OS X Server is a product from Apple that can be used as a server in multiple types of network settings, including with Linux. In the following paragraphs, we will discuss the relative merits and potential problems when you use each of these systems in your network.
4.5.1.1.1. Unix
Unix is a command line–based operating system that is still used in many organizations today. Often, the Unix server provides some type of line-of-business application that has been used by the organization for many years and would therefore be more trouble to move than the change would be worth. Unix servers can communicate with other servers and clients, but you some-times must install additional software to make them effective. For example, Microsoft clients can access Unix web servers with their browsers and no additional software, but access to a Unix file and print server requires that Services for Unix be installed on the client. Also, Unix servers cannot dynamically register their address with a WINS server, so you would need to add a static entry for the Unix server on the WINS server if you have legacy clients that use NetBIOS name resolution to find servers.
4.5.1.1.2. Linux
Linux is a Unix-like operating system that has some GUI capability. It is offered free to the public, and its code is open source and can be changed. Because there are so many versions of Linux, its tough to make a blanket statement about issues that you might encounter with Linux servers or clients. Some distributions of Linux are Red Hat, SuSE, Debian, and Caldera. The following are key features of the Linux operating system:
Multitasking
Linux supports multitasking, which is the ability to run several programs simultaneously.
Multiplatform
Linux is able to operate on various platforms, not just on Intel machines.
Multiprocessor support
Linux recognizes multiple processors on a single system.
Development
The source code is available in all noncommercial programs for Linux.
Virtual consoles
Linux supports virtual consoles, which are essentially independent logon sessions.
File system support
The native file system for Linux is EXT2, but Linux also supports FAT, HFS (for Macintosh), VFAT, and CDFS (for CD-ROMs).
Network support
Linux can connect to various network environments. It can support protocols such as TCP/IP, AppleTalk, and IPX/SPX.
With all of the features that Linux has, you might wonder where the problems could be. Well, typically the problems are not with the operating system itself, but rather with the user's ability to work with the system. People who are used to working with a Windows-based system will discover quickly that Linux is a very different environment. In addition, with so many distributions of Linux on the market, not all commands will work the same on all Linux servers and clients. If you decide to incorporate Linux into your network environment, you should standardize on a single distribution as much as possible and provide training for your users.
4.5.1.1.3. Mac OS X Server
Mac OS X Server is a product from Apple that combines the most popular technologies of the open source community with the latest version of Unix software. Mac OS X Server can be used with many different operating systems as a powerful web server and Internet server. All of this may sound fantastic, but it is not without its own challenges. The earlier versions of Mac OS X Server contained many bugs that prevented them from being able to communicate effectively with some Microsoft clients and some applications. Later versions have addressed most of these bugs and added new features to enhance compatibility. You should consult the latest information regarding compatibility issues with Mac OS X Server as part of incorporating it into your network. You can find this information on the vendor's website.
4.5.1.2. NetWare
NetWare is a fullfeatured operating system that offers all the functions required by an organization, such as file and print services, DNS, DHCP, FTP, and web servers, just to name a few. NetWare was once the server of choice for most organizations, but its popularity has declined sharply with the introduction of the newest Microsoft servers. NetWare is, however, still used in many organizations.
The biggest problems associated with NetWare will likely relate to making Microsoft clients and servers and Novell clients and servers talk to each other. In that regard, you should understand that both Novell and Microsoft have developed software products to provide common ground between Novell and Microsoft products. We discussed some of these products in Chapter 3; the following is a summary of the most common:
Client Services for NetWare (CSNW)
CSNW is a service that can be installed on Microsoft clients (along with the NWLink protocol) that allows them to connect directly to NetWare servers provided they have permissions to do so.
Gateway (and Client) Services for NetWare (GSNW)
GSNW is a service that can be installed on Microsoft servers that allows the server to become a gateway to a NetWare server for all of the clients that connect to the server. Installing GSNW installs the NWLink protocol as well.
File and Print Services for NetWare (FPNW)
FPNW is a service that can be installed on Nov-ell clients (which are typically Microsoft operating systems with Novell client installed on them) to allow the Novell client to access a Microsoft server, provided that it has permissions to do so.
Directory Service Manager for Netware (DSMN)
DSMN is a service that can be installed on Microsoft servers that allows them to see Novell NDS (Novell Directory Service) servers as they see Microsoft domain controllers. This service can be used to manage environments that include NDS and Active Directory.
As you can see, if you intend to combine Microsoft systems with Novell systems, then you have a few choices to make. These choices will also relate to the types of applications, protocols, and permission settings that you wish to use in your network.
4.5.1.3. Windows
Windows is by far the most popular operating system in use today. Windows offers many different types of clients and servers that have evolved over last 20 years. The latest Windows operating systems offer tremendous advantages over the earlier systems in regard to features, functionality, and especially security.
Since there have been so many different Windows clients and servers over the last 20 years, the challenge for many organizations is one of making all of the older servers and clients continue to communicate with the newer servers and clients. To understand this challenge more completely, you must also realize that the newer servers and clients are fundamentally different in their operation than the older (legacy) servers and clients. The following is a list of servers and clients offered by Microsoft Windows and the changes at each level of server or client:
Windows 3.1
This was the first Windows implementation. It was based on the DOS operating system but offered a basic GUI interface and multitasking capability. It did not offer networking.
Windows 3.11
This version of Windows contained all of the same features as Windows 3.1, but also offered the ability to network to other computers. It featured an early version of Microsoft Client.
Windows 95
This was the first 32-bit "operating system" from Microsoft. The reason that "operating system" is in quotes is that the true operating system was still DOS. In other words, Windows 95 was based on the DOS operating system.
Windows NT Workstation
This was the first Windows operating system that was not based on DOS but rather on the NT Kernel. Several versions of this operating system were released during the 1990s. The NT Kernel offered greater stability and reliability than previous operating systems. This Windows operating system offered some GUI capability, but not to the degree of Windows 95. One of the challenges with Windows NT Workstation was that the hardware list that was compatible with it was a much shorter list than that of Windows 95.
Windows 98
This was an enhanced version of Windows 95 that offered even greater GUI capabilities and enhanced support for applications and networking. It was still based on the DOS operating system.
Windows Me (Millennium Edition)
This was the last operating system in the family of Windows 9x clients. It was supposed to offer greater functionality and stability, but it was released too soon and contained many bugs. Because of this, Windows Me never picked up much of a following and therefore does not generally have a good reputation with network professionals.
Windows 2000 Professional
This system combined the stability of being built on the NT Ker-nel with the GUI capability like that of Windows 98. In addition, it offered more security options such as IPSec, Kerberos authentication, and MS-CHAP v2, just to name a few.
Windows XP
This is the latest and most fullfeatured client operating system. Also built on the NT Kernel, it combines stability with GUI features just like Windows 2000 Professional, but it also offers enhanced capabilities in regard to networking, fault tolerance, and security (especially after the latest Service Packs are installed).
Windows NT Server
This was the first Microsoft server. Built on the NT Kernel, it offered some stability and reliability, although not to the degree of Microsoft's latest offerings. Windows NT Server can be used as a domain controller. In addition, multiple domain controllers can be used in the same domain. When this is done, one of the domain controllers must be the Primary Domain Controller (PDC) and the other domain controllers are the Backup Domain Controllers (BDCs). All changes to the domain are then first made on the PDC and then replicated to all of the BDCs. This is referred to as single master replication. When you use newer Windows servers with Windows NT servers, you must take into account that the newer domains do not use this model of replication.
Windows 2000 Server
This version of Windows servers totally changed everything in regard to the methods that domain controllers use to replicate information as well as the security plat-forms that are used. It introduced Group Policies, which can be used to control user behavior and other security features. There are too many changes to list here. The main thing you should know is that there were so many changes that you can no longer assume that the new operating system will work seamlessly with all of the legacy clients and servers. The more new features you decide to use, such as Group Policies, Certificates, MS-CHAP v2, IPSec, and so on, the more you will have to make special provisions for any legacy clients, servers, or applications. The only way to avoid all of this is to upgrade everything.
Windows Server 2003
As of this writing, this is the latest Windows server offering from Microsoft. It enhances security by requiring a greater amount of configuration for clients to communicate and use resources. In other words, by default Windows Server 2003 is a more secure server than Windows 2000 Server. Windows Server 2003 offers all of the features, stability, and reliability of Windows 2000 Server, and then some. Windows Server 2003 configuration problems often stem from a lack of training or knowledge of the many configuration settings on the product. This can be addressed by requiring that your network professionals receive formal training specific to Windows Server 2003 products.
4.5.1.4. Appleshare IP
Appleshare IP is a server system that supports Macintosh clients using the Apple Filing Protocol (AFP). It also supports Windows clients using a system that emulates the SMB (CIFS) protocol. While Appleshare IP works rather seamlessly with Macintosh clients, there have been a large number of bugs in regard to its support of Microsoft clients. Newer versions of Appleshare IP have addressed many of these bugs. If you decide to implement an Appleshare IP server in your network, you should obtain the latest information about compatibility with all of the clients, servers, and applications that you intend to use.
4.5.2. Exam Essentials
Understand the basics of compatibility with Unix. Most clients can connect to Unix web servers with their browsers and no other special software. Microsoft clients can also use Services for Unix to connect to and use Unix file and print servers. You might need to include a static entry for a Unix server in dynamic name resolution databases such as WINS.
List the main advantages and disadvantages of Linux. Linux is a fullfeatured, GUI-based operating system with many variations, called distributions. The open source architecture of Linux software can sometimes make it more difficult to troubleshoot because not all commands work on all distributions. You should provide training for users and administrators who will use Linux in your network.
Describe the main advantages and disadvantages of Mac OS X Server. Mac OS X Server is a product from Apple that combines open source system flexibility with the latest version of Unix software. Mac OS X Server can be used with many different types of operating systems as a powerful web server and Internet server. Earlier versions of Mac OS X Server had many bugs in regard to communication with Microsoft clients, but most of these bugs have been fixed in the later versions. You can obtain the latest information about these bugs and fixes from the vendor's website.
Know how to combine NetWare with Microsoft servers and clients. The most likely problem that you will encounter with NetWare is its compatibility with other clients and servers. You have many options when connecting Microsoft clients to NetWare servers and connecting NetWare clients to Microsoft servers. You should know the differences between CSNW, GSNW, FPNW, and DSMN.
Describe how Microsoft Windows products have changed over time. There have been many versions of Microsoft Windows clients and servers over the last 20 years. The latest versions have featured major changes in operating systems and security requirements. All of these changes may cause previous operating systems not to work seamlessly with the newer servers and clients. The more new features of the latest clients and servers that you use, the greater the chance of having an issue regarding compatibility with legacy clients.
Know the basics of networking with Appleshare IP. Appleshare IP is a server system that supports Macintosh clients using the Apple Filing System and a TCP/IP protocol. Appleshare IP also supports Windows clients by using a version the SMB (CIFS) protocol. Earlier versions of Appleshare IP had many bugs in regard to communicating with Windows clients, but later versions have worked out most of the bugs.