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Part 2: Internet Networking

Figure 9-16. Configure access control and restrictions on the Access tab.

Click the Certificate button to launch the Web Server Certificate Wizard. This is the same wizard found in the Default Web Site Properties dialog box, and it will allow the creation of a new certificate or the installation of an existing one. Another set of security features is located by clicking the Connection button in the Connection Control section. The Connection dialog box allows the filtering of clients by their IP addresses. This can be done in one of two ways. All sites except those listed in the Computers box can be allowed access. This open, relaxed filtering method allows a few individuals to be filtered out and still ensures access to all other users who need it. The alternative option is to deny all users access except for those listed in the Computers box. This method is useful if there are only a few users using the service and/or security is extremely important.

To prevent inappropriate use of the SMTP server, click the Relay button in the Relay Restrictions section to control which computers can relay their mail. Anyone who has relay access will be able to use the SMTP server to relay e-mail messages from one source to another. Improperly secured SMTP sites are often exploited by spammers to anonymously relay unsolicited e-mail messages.

Messages

The Messages tab contains a number of settings affecting the types of e-mail notes that can be sent and received. This dialog box lets you limit the size of individual e-mails, limit the number or total size of e-mails transferred in a single session, and limit the number of recipients of a single e-mail. This last option keeps users from sending large numbers of spam messages through your server. Also, in the event that e-mail messages are undeliverable or they violate one of the configured restrictions, a location can be specified in the Badmail Directory box to house the offending e-mails.

Chapter 9: Using Internet Information Services

Delivery

E-mail is only useful if it gets to the intended recipient. Options on the Delivery tab are intended to give you the flexibility to set delivery options for optimal results. In the event that an initial attempt to deliver an e-mail note fails, the SMTP server has a retry interval setting. As you might assume, the retry interval is the period of time between repeating attempts to deliver a failed e-mail message. You can set intervals in minutes in the Outbound section for the first, second, third, and subsequent retries. Also on this tab are the Delay Notification options for setting the amount of time required before an administrative alert concerning the undelivered e-mail is sent. The Expiration Timeout settings let you define the length of time the message will be kept if it proves to be repeatedly undeliverable.

LDAP Routing

The LDAP Routing tab is used to integrate the SMTP server with a Windows domain running Active Directory directory services. Active Directory can then be used to resolve hosts and servers, assuming that the server contains records for the requested devices. Once LDAP routing is enabled (select Enable LDAP Routing), a server name and user credentials must be entered to complete the integration.

Security

The Security tab contains an option to add or remove user groups and accounts that will have operator permissions on the SMTP server. By default, only administrators are allowed this level of access.

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Part 3

Network Connectivity

Chapter 10

Workgroups and home networks have become very important in the past few years. With even the smallest of offices now using several computers as well as many homes containing more than one computer, workgroup networking has become more complex and more diverse. In fact, if you need to create a workgroup using Microsoft Windows XP or even other versions of Windows, you have more options than ever before. From a hardware point of view, you can easily create an Ethernet network, a HomePNA network, or a wireless network. You can also easily share an Internet connection, use Internet Connection Firewall (ICF) to protect the network, and use Windows XP to automatically set up your workgroup.

Workgroup refers to any network that does not use a centralized server for user authentication. Networks that rely on centralized servers for authentication, also known as domain-based networks, are discussed next in Chapter 11, “Understanding Domain Connectivity.” Workgroups usually comprise fewer than 20 computers and can be created in a home or office, or just about anywhere they are needed. This chapter assumes you have read Chapter 3, “Creating Network Connections,” where workgroup networking hardware is explored. This chapter also refers to Internet connections, which you can learn more about in Chapter 4, “Configuring Internet Connections,” and ICF, which you can learn more about in Chapter 5, “Using Internet Connection Firewall.”

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The physical arrangement of computers, hubs, shared printers, and such on a network is called the topology. The topology is a map of where your computers will reside and how they will connect to each other. Before you create a network, it is very important that you stop and think about your needs before you start moving computers around and installing network interface cards (NICs). As you think about the physical layout of the network, consider these questions:

●Do the computers reside in one room, or are they scattered throughout an office or home?

●What is your budget?

●How can you physically arrange the network and allow room for growth, but keep the networking topology as simple as possible?

●Is mobility in the home or office important? Should you consider a wireless network?

●How will an Internet connection be used? Will all clients share the same connection?

Simplicity is your best bet. As you are developing a workgroup design, remember that the simpler the design, the easier it will be to maintain. Sure, you might need a more complex workgroup configuration, but first ask yourself, “What is the easiest and most simple design I can use that will meet my needs?” This approach will help reduce the likelihood of setup and configuration problems, and it will probably save you money as well.

Once you answer these questions and determine the possible network topology that might be right for your workgroup, you can then begin to make some decisions about that topology. You might consider creating a preliminary sketch of the workgroup topology. Consider access to power outlets, phone outlets, and Internet accessibility for all locations as you make your sketch. Think about how the network might grow or change in the near future. As you are considering these issues, study the examples and illustrations in the following sections.

The simplest type of workgroup consists of computers that reside within the same room, such as in a small office or a home office. In this situation, you can use any type of network you like, such as Ethernet or HomePNA, or even Powerline or wireless.

In the following illustration, three computers are connected on an Ethernet network using a central hub. The network is contained in one room and is easy to set up.

A single room topology is, of course, the easiest configuration. Setup is simple. You can choose any type of networking hardware that you want to use, and it is unlikely that you will experience any networking problems. However, there are some specific negatives to consider:

●Wired limitations. The network is contained in a single room; therefore, if you use a standard wired Ethernet network, you will have to run cable to another room if the network expands beyond this room. You can avoid this potential problem by using a HomePNA, Powerline, or wireless network, or you can plan ways to add such a network to your wired network if computers are later added in another location.

●Physical constraints. Trying to use multiple computers in one room can be a headache. Often, the space required by keeping many computers in one place becomes prohibitive (particularly if you intend to use the room for other functions) unless special furniture is purchased to organize the machines. Also, you must consider the heat, noise, and access to power outlets.

●Fixed location. Unless you are using a wireless network, the single room design doesn’t give you a lot of flexibility. You must do all your computing

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from one location, which might not always be available or otherwise feasible. You’ll also find it more difficult to make significant changes to the network topology.

To learn more about Ethernet, HomePNA, and Powerline networks, see Chapter 3, “Creating Network Connections.” To learn about wireless networking, see Chapter 19, “Wireless Networking.”

Dispersed Topology

Dispersed topology often refers to a network connected across sites that are geographically distant from one another. In this book, dispersed topology refers to computers belonging to a single workgroup that are located in different rooms or floors of the home or a small office. This type of topology has become more common in workgroup configurations. For example, suppose there are three computers in your home: one in the living room, one in a home office, and one in a bedroom. You might want to create a home network so that the computers can communicate with each other and share Internet access. The same is true for an office setting where people work in several rooms and sometimes on different levels of a building.

A dispersed topology essentially works the same as a single room topology, but you might need to be more selective about the type of network you use. For example, if you want to use an Ethernet network, you might need to hire someone to run Category 5 cabling in the attic with drops into the rooms you need; otherwise, you’ll have cables running everywhere. A less expensive solution is to use a HomePNA network or a Powerline network. You might also consider using a wireless network. The following illustration shows a home network that uses HomePNA. A computer can connect to the network from any location in the office, as long as a phone jack is available.

HomePNA Network Spanning Two Rooms

Phone Phone

outlet outlet

The advantage of a dispersed network is flexibility. You can add or remove computers in different rooms as needed, including carrying a portable computer from room to room and connecting to the network wherever you want to work; however, your networking won’t be as fast as a wired network. Your network might also be more susceptible to interference from telephone signals with HomePNA, from power lines with Powerline, or from radio frequencies with wireless. You might incur more expenses installing a wired Ethernet network if it requires construction work, although the Ethernet NICs and hubs might be less expensive than similar wireless or HomePNA devices. These are all factors you’ll need to consider in planning your network.

Multi-Segment

A multi-segment network consists of two different networks that are linked together using a hardware device such as a switch or bridge. In this chapter, a multi-segment network refers to two networks connected together using Windows XP and its Network Bridge feature. Network Bridge in Windows XP allows you to easily connect two dissimilar network segments together seamlessly and without additional hardware. When you use a network bridge, a network interface card (NIC) for each network is installed on a single Windows XP computer. For example, in the following illustration, you can see that the Windows XP computer has an Ethernet NIC installed as well as a wireless NIC. Using Windows XP as a bridge, clients on the Ethernet network can seamlessly communicate with clients on the wireless network using Windows XP as the network bridge. Network Bridge can connect various combinations of internal or external network devices, including PCI cards, PCMCIA cards, USB devices, or IEEE 1394 devices.

Wired LAN Bridged with Wireless LAN

Wireless shared printer

Windows XP wired & wireless network bridge

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