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AOIT Computer Networking

Lesson 8Setting Up a Network Server

Teacher Resources

Resource Description

Teacher Resource 8.1 Answer Key: The Work of Network Servers Matching Activity

Teacher Resource 8.2 Inkshedding Stations: Setting Up Peer-to-Peer and Client/Server Networks

Teacher Resource 8.3 Demonstrations: Access and Authentication

Teacher Resource 8.4 Answer Key: Access and Authentication Practice

Teacher Resource 8.5 Student Roles: Client/Server Simulation Activity

Teacher Resource 8.6 Short-Answer Quiz: Setting Up Network Servers

Teacher Resource 8.7 Answer Key: Setting Up Network Servers Quiz

Teacher Resource 8.8 Key Vocabulary: Setting Up a Network Server

Teacher Resource 8.9 Bibliography: Setting Up a Network Server

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AOIT Computer NetworkingLesson 8 Setting Up a Network Server

Teacher Resource 8.1

Answer Key: The Work of Network Servers Matching Activity

Use this answer key as a guideline as you help students select statements that apply to each server.

Types of Network Servers

Statements about Servers

Web server7

1. Receives and processes input from players in multiplayer games

2. Stores a version of application software (such as Microsoft Word) that all clients on the network can use remotely

3. Stores files that users want to share with each other

4. Controls access to the network printer(s) and provides information about where your document is in the print queue

5. Takes on the role of a virtual post office and passes mail along toward its destination

6. May check user name and password as means of authentication

7. Delivers pages on request to clients using HTTP

8. Allows applications and users to search databases for selected records and passes results to other computers on the network

9. Stores returned web pages so that future requests can be accessed more rapidly

File server3

Database server8

Email server5

Game server1

Application server2

Print server4

Authentication server6

Proxy server9




Inkshedding Stations: Setting Up Peer-to-Peer and Client/Server Networks

Use these sheets to set up 10 stations where students will take notes on what they learn about different types of networks.

Setting Up StationsSet up stations before class starts by hanging the information provided for each station—text and diagrams—on the walls. Also, hang a blank sheet of chart paper next to each information display.

The stations will cover the following topics (the information for each is included in the following pages).

1. File Sharing in a Peer-to-Peer Local Area Network

2. The Three Security Methods on a Local Peer-to-Peer Network

3. Peer-to-Peer Networks on the World Wide Web

4. The Client/Server Network: Dedicated Servers

5. What a Typical Server Looks Like

6. Installing a Web Server on a Client Computer

7. Domain Controllers on Client/Server Networks

8. Network Address Translation

9. Proxy Servers

10. Domain Name System (DNS) vs. Windows Internet Naming Service (WINS)



Station 1

File Sharing in a Peer-to-Peer Local Area NetworkA peer-to-peer (P2P) network on a LAN allows computers to share hard drives, file folders, and networked resources such as fax machines and printers.

Peer-to-peer networks are typically used in small offices, homes, or schools. For example, students in a college dorm might connect their computers to a shared network and share music, video clips, pictures, or other files, and a printer. In this way, a peer-to-peer network is sort of like a YouTube for all sorts of files, but shared over a local network with only the people you trust, instead of the whole Internet.



Station 2

The Three Security Methods on a Local Peer-to-Peer Network

1. WorkgroupsAdding your computer to a “workgroup” (or a homegroup) allows you to share files with other computers in the same workgroup and access other folders shared by other computers in the same group.

The following shows the workgroups set up on one local area network that is used by college students who live together in the same dormitory household.

Only people who are members of the workgroup can see shared files. This means that Derrick can’t see Rita’s shared folders, because they don’t share a workgroup. No one can access Anne’s files, either, because she has her own workgroup.

2. PermissionsUsing permissions, you can decide how much control others have over your shared documents. There are three essential levels of file permissions you can set:

● Read Only: Other users can see (or load) the document, but they can’t edit it.

● Write Only/Change: Users can read, edit, or add to the document, but they can’t delete the file.

● Read & Write, or Full Access: Users have full control, and they can edit or delete the document.

3. PasswordsIn a workgroup, file security is the responsibility of the end user. Users can set access rights (permissions) to specific files and folders, using the login password for their local workstation.



Station 3

Peer-to-Peer Networks on the World Wide WebYou may have heard of people downloading music or movies from sites like BitTorrent—an activity that could be risky, as explained below. But this is one example of using a peer-to-peer network across the web. Here are some features of peer-to-peer networks on the web:

● Anyone who has the right software can connect to the network, from anywhere in the world.

● You select which folder to share with other people, and you add files you want to share.

● You can search other people’s folders for files they have shared.

● The program sets up a direct connection between the two computers transferring data.

● Security is really limited: many people share dangerous files on the web, to get you to download programs that can do your computer harm.

● It is illegal to download copyrighted material from a peer-to-peer site. You can be prosecuted.

● Criminals have used peer-to-peer networks to download other people’s tax forms or other important documents. They use the stolen information to commit fraud and theft. So be careful what you share!

If you use these networks, be careful! Follow these guidelines to protect yourself and your computer:

● Most important: Check the size of any file you want to download. If the size is different from what you expect it to be, it might be damaged or corrupted—or it might be a malicious software file that can hurt your computer.

● Share only a small number of files and don’t share any that contain personal information.

● If it’s a music file, preview during download to make sure it’s what you expected.

● Cancel anything that says it’s corrupted or damaged.



● Check the user agreement on the client program (BitTorrent, etc.) to make sure it doesn’t include adware and spyware with the application. If it collects a lot of information about you, it’s not worth it.

● If you start getting pop-up ads, stop using the program and uninstall it.

● Don’t download copyrighted material (music, videos, software programs). This is illegal, and your downloads can be tracked to your computer.

With BitTorrent, you are accessing the file(s) directly from one or more peer computers rather than a central file server. However, a central server has to know which clients are storing the file in the first place, so the initial request goes through the torrent server. But from that point forward, your computer is communicating directly with the peer computers. These peers are given designations: A peer that is sharing its file is known as a seeder. A peer that is downloading a file is known as a leecher.

The good thing about BitTorrent is that once a leecher has the file, it can turn around and become a seeder so that, over time, there are more seeders. This makes it easier for future leechers to download the file more rapidly.



Station 4

The Client/Server Network: Dedicated Servers Every client/server network has at least one computer that works only as a server. That is, these computers are dedicated to running only server software rather than normal applications. You wouldn’t log in and start typing an essay or browse the Internet on such a computer. Instead, the server performs important functions for other computers on the network.

Servers run server software. For example, web servers run a web server program like Apache, IIS (Microsoft), or Nginx (pronounced “engine x”). Most Windows-based servers will run in a Windows-based network operating system (NOS) such as Windows Server 2012 or Windows Server 2008. Many servers today, though, run in Linux or Unix. The most popular web server is Apache, and in most cases, it runs in Unix or Linux (although there is a version of Apache that can run in Windows). As of August 2015, it was estimated that about 50% of the web servers in operation run Apache.

Note that the NOS does not have to be from the same vendor or OS family as the client computers that it is servicing. Windows clients can and often do interface with Unix-based servers to store files, retrieve emails, or perform other network operations.

Types of Network ServersHere are some examples of types of servers:

● Web (HTTP) server: A web server stores all of the files (including any images, video, or audio) and file folders that make up a website. Client computers use a web browser to communicate with web servers, displaying returned web pages and issuing HTTP requests when the user clicks hyperlinks.

● Email server: An email server handles incoming and outgoing emails from clients. In your network, your email client program (such as Microsoft Outlook) prepares your email message and sends it to your server. Your server then sends the email on to the recipient’s email server. When that recipient runs his or her email client program, it connects to the recipient’s email server to receive any new emails. If you are sending an email to a user in your network, you still send the email to your server, but the server does not send it out to another server; instead, it just delivers it to the client when that user requests new email.

11. There are different protocols for email-server-to-email-server communication and email-client-to-email-server communication. Server-to-server communication is handled by SMTP (Simple Mail Transfer Protocol). Between a client and a server, there are two popular choices, IMAP and POP3.

● Proxy server: A proxy server is used to cache (store) web resources. The idea is that some files are going to be accessed by multiple users in the organization, so retaining them within the local network can save time. Proxy servers can also provide access control like a firewall by preventing some HTTP requests (such as those to websites that we want to block or those requesting certain content).

● Network address translation: This is not so much a server as a service provided by network gateways. The gateway controls access out to the Internet from the local network and from the Internet into the local network. The gateway can also translate IP addresses so that internal addresses are hidden from the outside world using network address translation (NAT). In most cases, the gateway presents only a single IP address to the outside world, which allows the organization to have many internal IP addresses while using only one IPv4 address on the Internet. This is known as many-to-one NAT.



● File server: File servers store files that many different people on the local network need access to. A client computer can access these files if its user first authenticates access (usually through a user name and password). The system administrator can also perform easy backups on the files on the server to better safeguard data files.

● Application server: This type of server stores the application software that all the client computers of the network will use. Instead of Microsoft Word being on your desktop, it would exist on the server machine, and your client computer would use it remotely. This was a very popular approach when hard disk drives were too expensive, leading to what was known as diskless workstations. Today, it is less common but allows easy control of licensed software that permits only a certain number of users at a time.

● Game server: Game servers are the authoritative source of events in a multiplayer video game. The server receives and processes each player’s input and then transmits enough data to allow its connected clients to maintain an accurate version of the game world to display to all players.

● Print server: A print server manages print requests and makes printer status information available to end users and network administrators. Print servers are used in both large and small networks, including home networks. In a large organization, a single dedicated computer serving as a print server might manage hundreds of printers. In a small office, a print server is often a specialized plug-in board or small network device about the size of a hub; it performs the same function as a dedicated print server but frees up valuable disk space on the office’s limited number of computers.

On small networks, one computer might house a few or all of these types of servers. On larger networks, there might be one or more servers for each function!



Simple Client/Server Network with One Dedicated Server



Station 5

What a Typical Server Looks LikeAlthough you can use a desktop computer as a server in your home or small business, most servers used in client/server networks have certain characteristics that enable them to serve many (thousands to millions of) requests at a time. Servers are engineered to manage, store, send, and process data 24 hours a day, so they have to be more robust and reliable than the typical desktop computer.

Server HardwareServers often run for long periods without interruption, and availability must often be very high, making hardware reliability and durability extremely important. Although servers can be built from commodity computer parts, mission-critical enterprise servers are ideally very fault tolerant and use specialized hardware with low failure rates in order to maximize uptime. For example, just a few minutes of downtime at a national stock exchange could justify the expense of entirely replacing the system with something more reliable.

Server hardware differs from typical desktop computer hardware as follows:

● Faster CPUs

● A larger amount of high-performance RAM

● Faster, higher capacity and a significant number of hard drives (for example, a server may have up to dozens of hard disks, whereas a normal desktop/laptop computer would have only one)

● Larger computer fans or water cooling to help remove heat

● Uninterruptible power supplies that ensure the servers continue to function in the event of a power failure

● Hardware redundancy, which means more than one instance of modules such as power supplies and hard disks arranged so that if one fails another is automatically available

o RAID technology uses several hard disk drives in a single cabinet. The extra storage space is used to record redundancy information so that any single disk failure can be recovered from by using the other disks and the redundancy data.

● Server casings that are usually flat and wide, adapted for storing many devices next to each other in a server rack

● Backup capabilities so that the contents of the server can easily be backed up, often daily

Operating SystemWhile nearly any personal computer is capable of acting as a network server, a dedicated server with a network operating system (NOS) is more suitable for data centers that serve large amounts of data. These types of servers are usually administered by qualified system administrators, so their operating systems are more tuned for stability and performance than for user-friendliness and ease of use. A large percentage of network operating systems are Unix/Linux-based. However, Windows-based servers such as Windows Server 2008 and 2012 are also used in large data centers.



Server RoomsServers need a stable power supply, good Internet access, and increased security. And they are noisy! Therefore, servers are usually stored in dedicated server centers or special rooms. A room of servers generates so much heat that server rooms are usually equipped with air-conditioning to keep the room cool enough for the servers to function correctly.



Several Servers in a Data Center Are Mounted on a Rack

Image retrieved from http://commons.wikimedia.org/wiki/File:Rack001.jpg on April 3, 2013, and reproduced here under the terms of the GNU Free Documentation License (http://en.wikipedia.org/wiki/en:GNU_Free_Documentation_License). Image courtesy of Jfreyre.



Station 6

Installing a Web Server on a Client ComputerSay you want to host your own website from your home computer. You want to continue to write essays, browse the Internet, and do everything else you normally do on the computer. But you also want the computer to work as a server and supply files to other computers that want to view your website.

You don’t have to run a server on a network operating system (NOS) to do this. You can use the operating system on your computer, such as Windows 7 or Windows 8. You will need to install the server software for the specific function you need (e.g., web server). Then your computer can function as a client computer to perform all your normal tasks, and also as a server. Keep in mind that if you did this, you would not want to shut down your computer, because the server would run all the time. You would also want to safeguard your personal files, because the server would be more open to network attack than a normal computer.

If you want others to be able to reach your website over the World Wide Web, a fixed IP address is usually required. Many Internet service providers (ISPs) assign dynamic IP addresses that can change from day to day. Fixed or static IP addresses are usually more expensive.

IIS (Internet Information Services)IIS is the web server that is packaged with most professional editions of Windows. You can install it on your computer in order to host your own website. For instructions on how to install IIS on a Windows 7 system, for example, visit the IIS website at http://learn.iis.net/page.aspx/28/installing-iis-7-on-windows-vista-and-windows-7.

Apache HTTP ServerApache is the most popular HTTP (web) server in use. As of August 2015, Apache was estimated to serve 50% of all active websites. It is an open source web server that you can download from the Apache website. Although Apache web servers are most commonly used with Unix/Linux operating systems, Apache is available for a wide variety of operating systems, including Windows.



Station 7

Domain Controllers on Client/Server NetworksOn Microsoft Windows servers, the domain controller stores information about people who use the network. The domain controller saves all this information centrally so that users can log in to any computer on the network with their unique user name and password and access all of the files and other information stored by the domain controller.

Profiles stored by the domain controller might include:

● Login names and passwords

● System settings (like the user’s desktop background, permissions, and preferences)

● Applications the user can access

● File folders and documents

The information is stored on a central server so that users can log in to any computer on the network and access their information and files. This feature is called roaming authentication.

The diagram above shows how different addresses are stored separately on company servers. The domain controller stores user profiles. These are separate from the computers’ IP addresses, which are assigned by a proxy server. And the users’ email address accounts are stored on a mail server.

In some networks, one server might perform all of these different functions. But the user profiles are still stored separately from IPs and email accounts.

Domain Controllers with Active DirectoryWindows Server 2012 and Windows Server 2008 both use a service called Active Directory, which blurs the line between the primary and backup domains. Active Directory stores profiles for all users on all the computers on the network, and profiles are updated all the time. So if the server fails, the user profiles are not lost. Other authentication servers include Kerberos (found in Windows) and LDAP (which can be found in Unix/Linux and Windows). LDAP is more than an authentication server but offers authentication services.



Station 8

Network Address TranslationA LAN’s gateway serves as the entrance to a local area network (LAN) from the Internet. Its role is like a router, since messages are routed from one LAN to another. But the gateway can also translate packets from one network protocol to another as they come into or leave the LAN. A gateway can also provide another service: network address translation (NAT).

NAT protects the internal network from possible external attacks by hiding internal IP addresses. It does this by using two separate sets of IP addresses: a public address that the Internet can see and a private one used on the local network.

The Internet service provider (ISP) assigns the entire local network one or more unique IP addresses. But the network’s computers still need a way to route messages to each other internally. So, the proxy server, using DHCP (Dynamic Host Configuration Protocol), also assigns a different IP address to each of the computers on the network.



Since the router has two IP addresses—one for the Internet and another for the LAN—it has to translate between them when traffic travels from inside the LAN to outside, on the Internet. This process is called network address translation.

The gateway assigns itself an internal address and uses DHCP to automatically assign IP addresses to each computer on the internal network. All the computers’ internal IP addresses are hidden from anyone outside the local area network. The whole LAN looks like one machine to anyone on the Internet because it is represented by only one IP address.

This setup has two benefits:

1. Different local area networks can reuse the same internal IP addresses.

2. The computers on the network are more protected and secure.

NAT Improves SecurityNetwork address translation helps to filter traffic coming into the network.

● It is one kind of firewall that can filter traffic based on IP addresses.

● It can block some pop-ups and spam from coming into the network.

● Additionally, all the messages that leave the network look like they are coming from the gateway server, not the internal computers.



Station 9

Proxy ServersA proxy server is used by an organization that wishes to make a web browser more efficient. The proxy server performs multiple functions, but its most significant function is to cache web content so that users can retrieve it locally instead of going back out across the Internet to retrieve content from the web server. Every computer that runs a web browser stores content in a local cache. Proxy servers extend this idea by having a sharable cache across the entire LAN.

Since all HTTP requests go to the local proxy server first, we can use the proxy server as a firewall. The proxy server tests all HTTP requests in the following ways:

● Is the content stored locally?

● Does the request meets certain guidelines, such as:

o Is it from inside the organization?

o Is it external?

o Did it come at a reasonable time of day? (e.g., an organization may block requests that come in over the weekend)

o Does it have a blocked destination host name? (the organization may choose to block all requests to Facebook, for example)

o Does it have a blocked URL? (e.g., the organization may want to block any URL that contains the word game in it)

If the request is stored locally and meets the required guidelines, the proxy server returns the content from its local store. This saves some time. If the request fulfills the second requirement (it meets guidelines) but it is not stored locally, then the proxy server forwards the request to the Internet. Upon receiving the response from the web server, the proxy server can scan the incoming message to ensure that it is appropriate.

In addition to serving as a type of firewall, the proxy server can offer one more thing to the organization: anonymity. Instead of sending out requests that contain the original client’s IP address, the proxy server attaches its own IP address to the request. In this way, the web server knows only that the proxy server requested the page; it doesn’t know who in the organization requested it.



Station 10

Domain Name System (DNS) vs. Windows Internet Naming Service (WINS)

Associating IP Aliases (Names) with IP AddressesOn the Internet, DNS stores the IP alias of various servers (such as www.google.com or wikipedia.org) and their IP addresses. When you type in www.google.com, DNS translates that IP alias into that machine’s IP address. It is the IP address that is placed into the TCP packet.

On a Windows-based LAN using DHCP, the same feat is accomplished using Windows Internet Naming Service (WINS), which uses NetBIOS names like “Laura’s Computer” for individual computers.

Domain Name System (DNS)

● Used on the Internet

● Example:

o IP Alias: www.google.com

o IP Address: 64.233.167.99

Windows Internet Naming Service (WINS)

● Used on a local Windows network

● Example:

o NetBIOS Name: Laura’s Computer

o IP Address: 172.16.1.15

Why Use DNS or WINS Instead of IP Addresses?● It’s easier to remember a name like Google than the address 64.233.167.99.

● Remembering a site’s name rather than its IP address is more fun, too!




Demonstrations: Access and AuthenticationUsing a computer and an LCD projector, perform the procedures outlined below as students follow along on their own computers. Refer to Teacher Resource 8.2 for additional information about each demonstration.

Activities

File Permissions in Peer-to-Peer NetworksNote: If teacher and student computers are blocked and you cannot access file sharing, there are other options:

● Connect two computers with a crossover cable.

● Use a computer that is not connected to your school’s network and show students the various settings using an LCD projector. You do not need a computer that has Internet access.

● Ask students to take some notes on file sharing and try looking at the menus on their home computers. Remind them that Internet access is not necessary.

Lead students through the process of viewing and changing file permissions in peer-to-peer networks. Explain that students can decide which folders to share and the level of permission they want to grant other users. They can share the whole drive or just specific folders. They can assign Read Only, Read/Write, depending on how much control they wish to give to other users.

Show students where they will be able to view and change these permissions on their computers.

File sharing on Windows 7 and 8 is quite streamlined. Simply go to the desired folder, right-click it, select “Share with,” and choose the level of security to give the homegroup, or select “Specific people” for a new dialog box where you can assign permissions based on specific user IDs.

Students can assign varying levels of permissions, which function as variations on the following:

● Read Only: You want your friend to read a poem you wrote but not to make any changes to your work.

● Read/Write: Your friend wrote an essay on your laptop computer, so now you want to share it with him and grant him full access to make changes or delete it.

Roaming Authentication on a Client/Server NetworkIn Inkshedding Station 7 (Teacher Resource 8.2), students studied how the Microsoft domain controller stores user profiles on a central server so that users can log in from any client machine. Show students the diagram from that station again, to illustrate how user profiles and other documents are stored separately.

Storing user profiles on central servers means that users don’t have to be tied to one client computer to access their information. All their user information, such as login name and password, documents, system settings, and preferences, are stored in a domain controller. If they are used to working at one desk but that computer fails, they can simply go to another computer on the network and log in to the server with their login and password.



When accessing files from the web, you are also using a client/server network. The computer with the web browser it uses to access a website is the client. The website is stored on a web server. When you visit a website, the client retrieves the web page files from a server over the Internet, as it would from an intranet on a local network.

In businesses, roaming authentication is used to control user access to shared folders and applications within the company network. A client/server network within a company is called an intranet, intra meaning “inside” (as opposed to inter, from Internet, which means “existing between” and suggests connection between).

Have students use a web browser to go to a site such as your local public library, where they can log in to an online account. Point them to the page that has account information, and explain that logging in to the website is called authentication.

Ask students whether they can also access this account from another computer at home, in the school library, or at a friend’s house. Explain that this is an example of what is called roaming authentication, because you can authenticate from many computers, or “roam.” Students may be familiar with the concept of roaming from their cell phone usage. Roaming is also used in cellular networks to authenticate your phone number on another provider’s network.

Mapping a Shared Drive—File Sharing on a Client/Server NetworkIn a peer-to-peer network, if someone shuts his or her computer down, the computer’s files are no longer available for others. One benefit of using a client/server network is that files are always available so long as the server is running.

When connected to a server, you can also map a shared network drive, so that it shows up under My Computer as if it were on the local machine. This is done by assigning a drive letter to the shared drive. The main hard drive’s letter of any computer is usually C, and additional ones might be assigned as E, F, and so on. When the letter appears with the network drive, it is “mapped” to the drive.

Here are the steps for mapping a network drive:

1. Open the Windows 7 Start menu and select Computer. Click Map Network Drive in the menu bar.For Windows 8, hold the mouse cursor in the extreme upper-right corner until the menu appears. Click Start. Right-click in an area of the screen where there is not a tile. At the bottom right of the screen, click All Apps. Then scroll over to the right until you see the Computer tile. Click that, and then select the Computer tab at the top and select Map Network Drive from the menu.

2. In the window that opens, select the drop-down list next to “Drive:”

3. Any drives that have already been mapped will show the folder name in the list. Select a drive letter that hasn’t been assigned yet.

4. Click the Browse button to find the shared network folder that you want to map.

5. If you want the computer to always recognize that drive, select “Reconnect at login.” Otherwise, the drive will be only temporarily connected while the user is logged in.

6. Click Finish.

Troubleshooting:

● If the disk letter was previously assigned to a different folder, a dialog box will ask whether you wish to disconnect the previous mounted drive.

● If it cannot be mapped, make sure the folder name is spelled correctly and correctly set up to be shared, and that the correct user name and password have been entered.



● To disconnect: Select My Computer > Tools and click Disconnect Network Drive.

Using ping and nslookup to Learn about DNSNote: If your student computers cannot access the command line, you can complete this activity by entering the command line prompts on your computer and then either displaying the transaction to students using an LCD projector or having students gather around your computer.

In Inkshedding Station 10, students read about DNS, which catalogs and stores the links between an IP alias and its IP address. Remind students that DNS is the Domain Name System that keeps track of these name-to-number conversions and stores the information.

You can use the ping and nslookup commands as described below to find IP addresses, but note that if the administrator has blocked ICMP packets on your school network, ping and nslookup will not work. Like traceroute, ping sends packets to an Internet destination to see if it responds and how long it takes to respond. It is often used for troubleshooting to see if a particular device is available and accessible.

Have students open the command prompt on their computers. Tell them there are a few ways they can find the IP addresses of common domains:

● Use the ping command to check if an Internet connection is active. On the command line, students can type ping cuteoverload.com (or use another popular website). Point out that they can type in the domain name, but the computer recognizes it as an IP number and shows them the address as it sends packets. Ping is a troubleshooting tool to check that an Internet connection is active and that the packets can be sent and received in a timely fashion.

● Use the nslookup command to get the server name as well as its IP address. Have students type nslookup ebay.com at the command line. The first address returned is the IP address of the DNS name server that they accessed to perform this lookup. Then the command also returns the domain name and host IP address.

Next, have students enter the IP address on the address line of their browser. For example, nslookup may show one of the IP addresses of eBay.com as something like 66.135.216.190. Have students type this IP address in their browser and see if they can access the eBay site in this way.

● Have students go to the website http://mxtoolbox.com/ReverseLookup.aspx. In the IP Address box, have them enter the IP address of whatever address they obtained from the nslookup step. They should obtain a PTR record (a pointer record) that points the IP address to the IP alias. For instance, if they used 66.211.160.87., they would see the domain name of eBay.com.

Using ipconfig to Learn about NAT and SubnetsNote: If your student computers cannot access the command line, you can complete this activity by entering the ipconfig/all command on your computer and then either displaying the transaction to students using an LCD projector or having students gather around your computer.

In Lesson 7, students used the ipconfig command to find their computer’s IP address. Now they can type the ipconfig command again and take a deeper look, to learn other important IP addresses on their network.

One example is the subnet. Explain that in a large or complex network, the network can be made both more secure and more efficient by assigning subnets to different departments or sections on the network. This adds another address to a portion of the network. The subnet in a network is like a street in a subdivision. In the subdivision, addresses have the same zip code, but you would take different routes to get to a specific house. All the subnets appear to be one network to the outside world. Because a local



area network may have several subnets, the network mask (or subnet mask) will differ between two computers of the same LAN if they are each on a separate subnet.

This brings us to network address translation (NAT), which students read about at Inkshedding Station 8.

Tell students that the way NAT works on the gateway is like a two-sided classroom door that leads in from the hallway. An identifying number or poster on the door is visible to anyone in the classroom, but those in the hall cannot see the inside of the door.

With the ipconfig/all command, students can see the internal, local IP address of their gateway router and DHCP server, which is like seeing what is inside the door. Then they can visit the website http://www.dslreports.com/whois, which shows the IP address that is beyond, broadcast from the local network to the Internet.




Answer Key: Access and Authentication PracticeUse this answer key as a guideline for students’ notes during the access and authentication hands-on practice.

Activity Name Type of Network(Peer-to-Peer or Client/Server)

What Did You Do?What Did You Learn?

File Permissions

Peer-to-Peer Editing file access and permission settings for documents

Roaming Authentication

Client/Server Accessing server accounts through a roaming profile

Mapping a Shared Drive

Client/Server Mapping a shared network drive to display on the local computer

Using ping Client/Server and Peer-to-Peer Using ping to check if an Internet connection is active

Learning how ping can be used in troubleshooting

Using nslookup

Client/Server Looking up the IP address and server name for a given domain name

Using ipconfig Client/Server Viewing ipconfig addresses for router and subnet mask, and comparing them with Whois information to see how the internal address differs from what is being broadcast to the Internet




Student Roles: Client/Server Simulation ActivityCut out the role-play strips (1–6) in this resource and distribute them, one to each group of students.

1

Who am I?

A desktop computer at 172.16.1.35. Your user name is Networking and your password is C0mput3rs.

What is my job?

Print a copy of MyReportCard.doc off of your shared file server.

2Who am I?

A desktop computer at 172.16.1.25.

What is my job?

Retrieve the NAF website at www.naf.org.

3Who am I?

A laser printer at 172.16.1.28.

What is my job?

When you get a request from the print server, 168.0.15.5, check to make sure you have paper. Then print documents.



4Who am I?

A web server on the Internet, at www.naf.org or 208.68.173.167.

What is my job?

Host the NAF website files.

When a request comes in, send back the status line “HTTP/1.1 200 OK” along with your message or files in response to the request.

5

Who am I?

A LAN gateway router with a local address at 168.0.0.1 and an Internet address at 66.235.202.61.

What is my job?

When you receive a request from a local computer, direct it to the proper address. If it starts with 168 or 172, you know it is on the local network. If it is another address, you know it is on the Internet. To send an Internet request, you must use network address translation.

First, log which computer on the network sent the request to you. Then change the addresses on the message so that it shows the origin address as your network’s Internet address, 66.235.202.61.

Send the message along. When you get a reply back, check your log to see which local computer sent the request, and forward the reply to that computer.

6Who am I?

A LAN file and print server at 168.0.15.5.

What is my job?

You store files on the local network and share them with users, but only those who have a password. The password is C0mput3rs.

Note: You may consider adding two more to this list:

● A gateway: The person representing the gateway would be very “nosey,” standing near the door and deciding who can enter based on the message the person carries. A router can filter based only on IP address or where a message comes from.



● A proxy server: The person representing the proxy server makes a copy of every piece of information coming into the room and decides if it should be forwarded to the requester and then intercepts every request to see if he/she already has a copy to return immediately. This person may block responses and requests based on their content.




Short-Answer Quiz: Setting Up Network Servers1. Explain how network workgroups or homegroups are used and how they help users share files.

2. What are two differences between sharing files in a peer-to-peer LAN and using peer-to-peer file sharing on the Internet?

3. What are some of the roles a dedicated server might play in a client/server network?

4. What kind of network uses roaming authentication, and how does it work?

5. Describe how network address translation (NAT) hides the addresses of computers on a local area network from computers on the Internet.

6. What is the Domain Name System (DNS) on the Internet, and what is the comparable service on a Windows LAN?

7. What does it mean to map a shared drive in a client/server network?

8. What information can you learn from using the ipconfig command at the command prompt?




Answer Key: Setting Up Network Servers Quiz1. Explain how network workgroups or homegroups are used and how they help users share files.

2. Workgroups or homegroups are used on peer-to-peer networks. Each computer joins a workgroup or homegroup, and users can share files with the other computers in their group.

3. What are two differences between sharing files in a peer-to-peer LAN and using peer-to-peer file sharing on the Internet?

o One is local and one is wide area.

o Peer-to-peer file sharing on a LAN uses shared file folders and settings configured in the operating system, while sharing on the web requires a special software client like Napster, BitTorrent, and so on.

o Passwords and permissions can be set in the LAN, but in a peer-to-peer network on the web, there is no authentication or protection when sharing files with other users.

o In a LAN, you can see the names of people’s computers and workgroups, but you don’t see the names of users on the web. (However, in peer-to-peer file sharing, your computer IP address can be traced back to you—as the RIAA and MPAA lawsuits have demonstrated.)

o On the web, you have to be careful about files that you try to download. They may contain viruses or other forms of malware.

4. What are some of the roles a dedicated server might play in a client/server network?

5. A dedicated server might function as a proxy server, an email server, a web server, an application server, a file server, a print server, a game server, or a database server. A dedicated server might serve multiple functions in a small network.

6. What kind of network uses roaming authentication, and how does it work?

7. A client/server network can use roaming authentication to verify users’ identities when users log in to client computers. The server requires people who want to access the server from a client computer to authenticate themselves by providing their user name and password. Since the information can be accessed remotely, this allows people to log in to any client machine on the network—hence the term roaming authentication.

8. Describe how network address translation hides the addresses of computers on a local area network from computers on the Internet.

9. A gateway router possesses two IP addresses: one visible to the computers in the LAN and one visible to external computers on the Internet. Computers on the local network see the internal address. Computers outside the network see only the gateway’s external address. When traffic leaves the local network, the gateway hides the internal addresses by representing the whole local network with its external IP address.

10. What is the Domain Name System (DNS) on the Internet, and what is the comparable service on a Windows LAN?

11. DNS stores the information correlating an IP address to its IP alias, such as Google.com. This makes it easier for users to remember the “address” for a given web domain. On a local network, Windows machines use Windows Internet Naming Service, or WINS, to assign a NetBIOS name to a host computer.



12. What does it mean to map a shared drive in a client/server network?

13. A drive that stores files on a server can be mapped to a local computer by assigning the drive a local drive letter. Doing so provides a shortcut from the local computer to the remote host server and makes the drive appear to be stored on the local computer.

14. What information can you learn from using the ipconfig command at the command prompt?

15. The ipconfig command can reveal a local network’s IP address configurations for the devices attached to the network—such as client computers, the gateway router, and printers or fax machines—as well as for the subnets.




Key Vocabulary: Setting Up a Network ServerTerm Definition

Active Directory A Windows database used to store information about users, such as their user names, passwords, and system preferences, and the shared resources they are authorized to use.

Apache The most popular web server in use today. It primarily runs on Unix/Linux computers but can also run in Windows.

authentication The login process used to ensure that a user is who he or she claims to be and should be granted network access.

authorization The process of granting or denying access to specific network resources based on the user’s identity.

backup Files from a computer hard disk stored on other media to ensure that the data is available if the hard disk fails. Popular backup media: external hard disk, USB drive, magnetic tape. Backing up an organization’s files is easier if the organization stores all files on a file server.

BitTorrent An application for peer-to-peer file sharing where one computer obtains a file directly from one or several other peer computers instead of from a server.

centralized A client/server network is a centralized system, meaning the server provides resources in one central location for other remote computers to access.

dedicated server A computer used exclusively as a network server, providing shared network resources or performing network tasks.

domain controller A basic type of Microsoft Windows server that stores user profiles and controls user authentication and security on a client/server network.

Domain Name System (DNS)

An Internet service that translates IP aliases (such as www.google.com) into IP addresses. Networks rely on numeric values, but names are easier for humans to remember.

drive mapping The process of creating a shortcut and assigning a drive letter to a shared network drive, so that the drive appears to be located on the local computer.

gateway A network device that sits at the edge of the local network and connects to the Internet. It can use network address translation to make it appear as if all LAN traffic has originated at the gateway IP.

homegroup A Windows 7 and 8 feature that simplifies sharing files between machines on the same network.



host A computer system that stores files or information for other computers to access via the network—such as a web host that stores website files, or a client sharing files on a peer-to-peer network.

IIS (Internet Information Services) An alternate web server to Apache that runs only in Windows.

ipconfig A command used to display the IP addresses for the local network, including the computers, routers, subnets, and more.

network address translation (NAT)

An Internet standard that enables a router to use one IP address for external (Internet) traffic and a separate one for internal (LAN) traffic.

network operating system (NOS)

An operating system used by a server; provides capabilities beyond a regular operating system to run a client/server network.

nslookup A command for obtaining the IP address of an IP alias. The program can be used for diagnosing DNS problems. When a network is functioning properly, using nslookup for a web domain will display the host server, its IP address, and the address associated with the domain name.

permissions In a peer-to-peer network, files can be shared with one of two permission levels: Read Only and Read/Write. Files can be password protected.

ping A program used at the command line to test the accessibility and speed of a connection to another network resource.

proxy server A proxy server is used by an organization to cache web content so that users can retrieve content more quickly than if they had to make duplicate requests of a web server. The proxy server can also filter content, disallowing content that the organization does not want its users to have access to.

roaming The capability of logging in to a network from multiple locations. In local area networks, it means that user information is stored on a network server, and users can access their system preferences and files and access shared resources from multiple client workstations.

segment One section of a LAN that is used by a particular workgroup or department and separated from other segments by bridges, routers, or switches. Subnets can also segment networks.

server room A room housing one or more servers. The room is usually off limits to most people to keep it clean and orderly. It often has a separate air-conditioning facility to ensure that the servers cannot overheat.

subnet A portion of a LAN that shares the same part of an IP address.

user profile A profile containing desktop settings, preferences, and so on that Windows uses to keep track of users.

web server A server that hosts a website or other files and is available for



computers on the Internet or intranet to access.

workgroup Client systems on a peer network can join a workgroup to share files with other systems in the same group.




Bibliography: Setting Up a Network ServerThe following sources were used in the preparation of this lesson and may be useful for your reference or as classroom resources. We check and update the URLs annually to ensure that they continue to be useful.

PrintLowe, Doug. Networking All-In-One Desk Reference for Dummies, 2nd ed. Indianapolis, IN: Wiley, 2005.

Online“Apache Market Share Report, Nov 2015.” Perfect Leads, http://www.perfectleads.com/marketshare/apache (accessed November 2, 2015).

Becker, Ralph. “IP Addressing.” IP Address Subnetting Tutorial, http://www.ralphb.net/IPSubnet/ipaddr.html (accessed November 2, 2015).

“Domain Name System.” Wikipedia, http://en.wikipedia.org/wiki/Domain_Name_System (accessed November 2, 2015).

“Hypertext Transfer Protocol.” Wikipedia, http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol (accessed November 2, 2015).

Laurie, Victor. “TCP/IP and Networking Tools.” CommandWindows.com, http://commandwindows.com/tcpiputil.htm (accessed November 2, 2015).

“Server (Computing).” Wikipedia, http://en.wikipedia.org/wiki/Server_(computing) (accessed November 2, 2015).

Tyson, Jeff. “How Network Address Translation Works.” HowStuffWorks, http://computer.howstuffworks.com/nat.htm (accessed November 2, 2015).

“What Is a Network Operating System?” wiseGeek, http://www.wisegeek.com/what-is-a-network-operating-system.htm (accessed November 2, 2015).


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