i need a detailed notes on hardware and networking?

Answer 1

Networking:
http://ocw.mit.edu/OcwWeb/Electrical-Engineering-and-Computer-Science/6-829Computer-NetworksFall2002/CourseHome/index.htm
http://ocw.mit.edu/OcwWeb/Electrical-Engineering-and-Computer-Science/6-263JData-Communication-NetworksFall2002/CourseHome/index.htm
http://www.venu4u.info/network/datacom.html

Hardware:
http://ocw.mit.edu/OcwWeb/Electrical-Engineering-and-Computer-Science/6-823Fall-2005/CourseHome/index.htm

Answer 2

Buy a book.

http://books.google.com/books?q=detailed+notes+on+hardware+and+networking&ots=fgOgvH9R6F&sa=X&oi=print&ct=title

Answer 3

Wireless Networks
What I know

Begin with the high speed DSL or cable service. As far as I know, wireless networks would need one of these, although it is not certain that a simple wireless network needs a dedicated line; it might work with a dial-up but configuring the wireless router might be impossible since it seems to depend of internet access to do so.
Assuming broadband is available, the next step would be to install a wireless router, such as a Linksys WRT54G, a device capable of speeds up to 54 Mbs. The device itself has an internet-like address of 192.168.1.1 and each device attached to or accessing it has an address which converts the last digit to the form 100 or 101 and so forth. Thus, a laptop with a wireless card might be address 192.168.1.101. One can access and configure a Linksys router by entering the address 192.168.1.1 into a web browser and is immediately presented the configuration screen. The person doing the configuration change must have the user name and password originally entered at the time the device was installed, assuming the person installing it changed the default factory user name and password. The Linksys router is installed by first attaching your main computer to the DSL or cable modem, then using the supplied software on the CD accompanying the router, following the steps as directed on the installation CD. It directs you to attach an Ethernet cable from your computer to the modem, either DSL or cable, then arranging the wires from wall outlet or TV cable to the modem, then from the modem to the router, plugging cables into the jacks as shown. If one follows this set of instructions, internet access is immediately available through the router.
A simple wireless network need not be entirely wireless. One or more computers can be wired to the router, usually up to a limit of four, plus other wireless devices. The Linksys routers are limited to 253 devices and defaulted to 50 total devices, but realistically it is not likely anyone would attach that many to a network. My original configuration had the desktop wired to the router via Cat 5 ethernet cable and the laptop using a wireless card. Later I installed a Netgear USB adapter to the desktop and converted it to wireless. The advantage of attaching the “main” computer by cable is that the speed is much faster, around 100 Mbs compared to 54 using wireless, although Netgear makes a wireless router capable of 100 Mbs.This higher speed would be an advantage when two devices on the network are exchanging files or accessing a shared printer.
Having installed the router, the next step is installing or inserting a wireless adapter in each computer. This usually implies installing drivers and/or utilities supplied with the device on a CD. If the main computer is wired to the router, it is only necessary to attach the Cat 5 cable from the back of the computer to one of the available ports on the router. The computer must have an Ethernet (RJ45) port built in or a network card installed to do this. At this point, no network exists, but internet access at each computer, wireless or wired, normally comes on automatically with little trouble by the user.
Now for setting up a true network. Assuming each computer is running Windows XP, the next step is allowing Windows to create the network. On each computer it is necessary to go to the Control Panel and select Network Connections, then select Network Setup Wizard. Windows will construct the network using the names of the computers involved and the name of the network which you gave the wireless router. Simply follow the windows presented making sure you know the name you have given to that computer and the name you gave the network when you installed the router. Where are the names to be found? The computer name is located internally and is accessed by going to the Control Panel and selecting System. A tab is labeled Computer Name and it also has the workgroup name. The workgroup name is not necessarily the same as the network name. In fact it is not clear to me what purpose the workgroup name plays. Once you have run the network setup on all computers in the net, then it is essentially created.

Shared folders and printers
If you expect to move data back and forth from one computer in the network to another one, it is necessary to define shared folders in each computer. Suppose you have a folder containing WordPerfect documents in computer A and you intend to access those from computer B. On computer A, using Windows Explorer, drag the folder containing those documents to the folder named Shared Folders. Doing so tells that computer that you want that folder to be a shared folder, that is, open to use by other computers in your network. Now you must go to computer B and define that folder (on A) as a Network Drive. To do this, go to Control Panel, Network Connections and click on Tools. Then click on Map Network Drive. You will see that the Drive Z is displayed, but you can define any unused drive from E to Z. Click on Browse and follow the path to the other computer and the shared folder(s). The computers both know that any document on computer A can be accessed from any other computer which has defined a Network Drive. It is admittedly cumbersome and there is no doubt that Windows could have made it much more friendly and understandable. But you have to work with what is available and that is what Microsoft gave us. Defining a network drive is probably a carry-over from a decade old software called LAN Server marketed by Microsoft and IBM.
Defining a shared printer on another computer is somewhat easier. Start by going to the Control Panel on the computer which has no printer and selecting Printers and Faxes, then Add Printer. You will be presented with a Wizard for installing it. Make sure you select Network printer when presented with that option and if you don’t know the printer name (on the computer which connects to the printer), then click on Browse. You should have written down the printer name from the other computer, however. On the computer which has the printer, right click on the printer and click on Properties. Make sure the option to share this printer is selected by going to the Share tab. Since both computers now know that you want to share the printer, it is ready for printing. One caution however. The computer and printer and must remain on in order for others to use it. If turned off, the network assumes you have no printer. The same holds true for sharing documents or other objects. The computer housing them has to be ON in order for others to access them.
So what happens if you sell that printer, or install another one on the computer housing the shared printer? Then you have to go through that printer definition again, making sure you define that printer as a shared printer when you install it.

Security
When you install the router, you will probably want to get it up and running to see if you can access the internet as quickly as possible. Nothing wrong with that. But eventually you will want to go back and define stringent security on the network and you will do so by configuring security on your wireless router. My experience is with a Linksys device and it is this which I will use as an example.

MAC addresses You should enable Media Access Control (MAC) filtering. Media Access Control is an address assigned to each wireless card. All wireless devices have unique MAC addresses. The address includes six sets of paired characters and is usually printed on the back of your wireless card. MAC filtering tells your router/access point to grant access only to MAC addresses you enter.This will help keep out unwanted users who might otherwise gain access to your network, through the router.

WEP You should always use encryption. There are two standards of encryption. Wired Equivalent Privacy (WEP) is an older and less secure method. It uses a non-changing 64- or 128-bit key. Although it's not the best encryption, it is better than nothing. Defining WEP is done on the router, using the software supplied with the router. On the Linksys router this is done by entering the web address 192.168.1.1 in any browser such as Netscape Navigator or Internet Explorer, which takes you to the router itself and a screen requiring you to enter your user name and password (hopefully you remember them or wrote them down). Then you click on the Wireless tab and select Wireless Security. You will then be required to select either 64 or 128 bit option and enter a passphrase, then click on Generate. Doing so generates four keys which are then displayed. Write the passphrase and the keys down and go to each computer and make sure that the network adapter has picked this up, or enter them through the supplied software which came with the adapter. The Netgear adapter picked it up without having to enter, as did the Dell (Broadcom) adapter on the notebook computer.

Broadcasting the SSID (Service Set Identifier)1. Stop broadcasting to the world. By default, most access points send a short message repeating the network's name. The network's name is called the SSID. Anybody who lives (or drives) nearby can easily detect that you have a wireless network, find its name and jump onto it. By disabling the SSID broadcast, you are no longer telling the world around you that you have a wireless network. Additionally, rename the SSID. Don't use your name or something easily identifiable. Doing so only makes it easier for someone to hack into it.

The wireless router you use comes with no security, a generic SSID, and other factory settings. This is done to make it easier to install without confounding the purchaser. These default settings should be changed immediately for your own protection.
My network settings
Net name(SSID)
Router name and password
WEP settings
passphrase
Key 1
MACs
Notebook
Desktop
MAC filtering is ON
Computer names
Dell Dimension 3000
Dell Inspiron 1000
Shared printer name

Appendix A: Troubleshooting
This appendix consists of two parts: “Common Problems and Solutions” and “Frequently Asked Questions.” Provided are possible solutions to problems that may occur during the installation and operation of the Router. Read the descriptions below to help you solve your problems. If you can’t find an answer here, check the Linksys website at www.linksys.com.
Common Problems and Solutions
1. I need to set a static IP address on a PC.
You can assign a static IP address to a PC by performing the following steps:
• For Windows XP:
The following instructions assume you are running Windows XP with the default interface. If you are using the Classic interface (where the icons and menus look like previous Windows versions), please follow the instructions for Windows 2000.
1. Click Start and Control Panel.
2. Click the Network and Internet Connections icon and then the Network Connections icon.
3. Right-click the Local Area Connection that is associated with the Ethernet adapter you are using, and select the Properties option.
4. In the This connection uses the following items box, highlight Internet Protocol (TCP/IP). Click the Properties button.
5. Enter a unique IP address that is not used by any other computer on the network connected to the Router.
6. Enter the Subnet Mask, 255.255.255.0.
7. Enter the Default Gateway, 192.168.1.1 (Router’s default IP address).
8. Toward the bottom of the window, select Use the following DNS server addresses, and enter the Preferred DNS server and Alternative DNS server (provided by your ISP). Contact your ISP or go on its website to find the information.
9. Click the OK button in the Internet Protocol (TCP/IP) Properties window. Click the OK button in the Local Area Connection Properties window.
2. I want to test my Internet connection.
A Check your TCP/IP settings.
For Windows 2000 and XP:
• Click Start and Run. In the Open field, type cmd. Press the Enter key or click the OK button. In the command prompt, type ping 192.168.1.1 and press the Enter key.
• If you get a reply, the computer is communicating with the Router.
• If you do NOT get a reply, please check the cable, and make sure Obtain an IP address automatically is
selected in the TCP/IP settings for your Ethernet adapter.
C In the command prompt, type ping followed by your Internet or WAN IP address and press the Enter key.
The Internet or WAN IP Address can be found on the Status screen of the Router’s web-based utility. For example, if your Internet or WAN IP address is 1.2.3.4, you would enter ping 1.2.3.4 and press the Enter key.
• If you get a reply, the computer is connected to the Router.
• If you do NOT get a reply, try the ping command from a different computer to verify that your original computer is not the cause of the problem.
D In the command prompt, type ping www.yahoo.com and press the Enter key.
• If you get a reply, the computer is connected to the Internet. If you cannot open a webpage, try the ping command from a different computer to verify that your original computer is not the cause of the problem.
• If you do NOT get a reply, there may be a problem with the connection. Try the ping command from a different computer to verify that your original computer is not the cause of the problem.
5. I am not getting an IP address on the Internet with my Internet connection.
• Refer to “Problem #2, I want to test my Internet connection” to verify that you have connectivity.
1. If you need to register the MAC address of your Ethernet adapter with your ISP, please see “Appendix D: Finding the MAC address and IP Address for Your Ethernet Adapter.” If you need to clone the MAC address of your Ethernet adapter onto the Router, see the System section of “Chapter 6: The Router’s Web-based Utility” for details.
2. Make sure you are using the right Internet connection settings. Contact your ISP to see if your Internet connection type is DHCP, Static IP Address, or PPPoE (commonly used by DSL consumers). Please refer to the Setup section of “Chapter 6: The Router’s Web-based Utility” for details on Internet connection settings.
3. Make sure you have the right cable. Check to see if the Internet column has a solidly lit Link/Act LED.
4. Make sure the cable connecting from your cable or DSL modem is connected to the Router’s Internet port. Verify that the Status page of the Router’s web-based utility shows a valid IP address from your ISP.
5. Turn off the computer, Router, and cable/DSL modem. Wait 30 seconds, and then turn on the Router, cable/DSL modem, and computer. Check the Status tab of the Router’s web-based utility to see if you get an IP address.
6. I am not able to access the Setup page of the Router’s web-based utility.
• Refer to “Problem #2, I want to test my Internet connection” to verify that your computer is properly connected to the Router.
1. Refer to “Appendix D: Finding the MAC Address and IP address for Your Ethernet Adapter” to verify that your computer has an IP Address, Subnet Mask, Gateway, and DNS.
2. Set a static IP address on your system; refer to “Problem #1: I need to set a static IP address.”
3. Refer to “Problem #10: I need to remove the proxy settings or the dial-up pop-up window (for PPPoE users).”

7. I need to set up a server behind my Router and make it available to the public.
To use a server like a web, ftp, or mail server, you need to know the respective port numbers they are using. For example, port 80 (HTTP) is used for web; port 21 (FTP) is used for FTP, and port 25 (SMTP outgoing) and port 110 (POP3 incoming) are used for the mail server. You can get more information by viewing the documentation provided with the server you installed.
• Follow these steps to set up port forwarding through the Router’s web-based utility. We will be setting up web, ftp, and mail servers.
1. Access the Router’s web-based utility by going to http://192.168.1.1 or the IP address of the Router. Go to the Applications & Gaming => Port Forwarding tab.
2. Enter any name you want to use for the Customized Application.
3. Enter the External Port range of the service you are using. For example, if you have a web server, you would enter the range 80 to 80.
4. Check the protocol you will be using, TCP and/or UDP.
5. Enter the IP address of the PC or network device that you want the port server to go to. For example, if the web server’s Ethernet adapter IP address is 192.168.1.100, you would enter 100 in the field provided. Check “Appendix D: Finding the MAC Address and IP Address for Your Ethernet Adapter” for details on getting an IP address.
6. Check the Enable option for the port services you want to use. Consider the example below:
Customized External Port TCP UDP IP Address Enable Application
Web server 80 to 80 X X 192.168.1.100 X
FTP server 21 to 21 X 192.168.1.101 X
SMTP (outgoing) 25 to 25 X X 192.168.1.102 X
POP3 (incoming) 110 to 110 X X 192.168.1.102 X
When you have completed the configuration, click the Save Settings button.
8. I need to set up online game hosting or use other Internet applications.
If you want to play online games or use Internet applications, most will work without doing any port forwarding or DMZ hosting. There may be cases when you want to host an online game or Internet application. This would require you to set up the Router to deliver incoming packets or data to a specific computer. This also applies to the Internet applications you are using. The best way to get the information on what port services to use is to go to the website of the online game or application you want to use. Follow these steps to set up online game hosting or use a certain Internet application:
1. Access the Router’s web interface by going to http://192.168.1.1 or the IP address of the Router. Go to the Applications & Gaming => Port Forwarding tab.
2. Enter any name you want to use for the Customized Application.
3. Enter the External Port range of the service you are using. For example, if you want to host Unreal Tournament (UT), you would enter the range 7777 to 27900.
4. Check the protocol you will be using, TCP and/or UDP.
5. Enter the IP address of the PC or network device that you want the port server to go to. For example, if the web server’s Ethernet adapter IP address is 192.168.1.100, you would enter 100 in the field provided. Check “Appendix D: Finding the MAC Address and IP Address for Your Ethernet Adapter” for details on getting an IP address.
6. Check the Enable option for the port services you want to use. Consider the example below:
Customized External Port TCP UDP IP Address Enable
Application
UT 7777 to 27900 X X 192.168.1.100 X
Halflife 27015 to 27015 X X 192.168.1.105 X
PC Anywhere 5631 to 5631 X 192.168.1.102 X
VPN IPSEC 500 to 500 X 192.168.1.100 X
When you have completed the configuration, click the Save Settings button.
9. I can’t get the Internet game, server, or application to work.
If you are having difficulties getting any Internet game, server, or application to function properly, consider exposing one PC to the Internet using DeMilitarized Zone (DMZ) hosting. This option is available when an application requires too many ports or when you are not sure which port services to use. Make sure you disable all the forwarding entries if you want to successfully use DMZ hosting, since forwarding has priority over DMZ hosting. (In other words, data that enters the Router will be checked first by the forwarding settings. If the port number that the data enters from does not have port forwarding, then the Router will send the data to whichever PC or network device you set for DMZ hosting.)
• Follow these steps to set DMZ hosting:
1. Access the Router’s web-based utility by going to http://192.168.1.1 or the IP address of the Router. Go to the Applications & Gaming => Port Forwarding tab.
2. Disable or remove the entries you have entered for forwarding. Keep this information in case you want to use it at a later time.
3. Go to the Applications & Gaming => DMZ tab.
4. Select Enable next to DMZ. In the DMZ Host IP Address field, enter the IP address of the computer you want exposed to the Internet. This will bypass the NAT technology for that computer. Please refer to “Appendix D: Finding the MAC Address and IP Address for Your Ethernet Adapter” for details on getting an IP address.
• Once completed with the configuration, click the Apply button.
10. I forgot my password, or the password prompt always appears when I am saving settings to the Router.
• Reset the Router to factory default by pressing the Reset button for 10 seconds and then releasing it. If you are still getting prompted for a password when saving settings, then perform the following steps:
1. Access the Router’s web-based utility by going to http://192.168.1.1 or the IP address of the Router. Enter the default password admin, and click the Administrations => Management tab.
2. Enter a different password in the Router Password field, and enter the same password in the second field to confirm the password.
3. Click the Save Settings button.
11. I am a PPPoE user, and I need to remove the proxy settings or the dial-up pop-up window.
If you have proxy settings, you need to disable these on your computer. Because the Router is the gateway for the Internet connection, the computer does not need any proxy settings to gain access. Please follow these directions to verify that you do not have any proxy settings and that the browser you use is set to connect directly to the LAN.
• For Microsoft Internet Explorer 5.0 or higher:
1. Click Start, Settings, and Control Panel. Double-click Internet Options.
2. Click the Connections tab.
3. Click the LAN settings button and remove anything that is checked.
4. Click the OK button to go back to the previous screen.
5. Click the option Never dial a connection. This will remove any dial-up pop-ups for PPPoE users.
• For Netscape 4.7 or higher:
1. Start Netscape Navigator, and click Edit, Preferences, Advanced, and Proxies.
2. Make sure you have Direct connection to the Internet selected on this screen.
3. Close all the windows to finish.
12. To start over, I need to set the Router to factory default.
Hold the Reset button for 10 seconds and then release it. This will return the password, forwarding, and other settings on the Router to the factory default settings. In other words, the Router will revert to its original factory configuration.
13. I need to upgrade the firmware.
In order to upgrade the firmware with the latest features, you need to go to the Linksys website and download the latest firmware at www.linksys.com.
• Follow these steps:
1. Go to the Linksys website at http://www.linksys.com and download the latest firmware.
2. To upgrade the firmware, follow the steps in “Appendix C: Upgrading Firmware.”
14. The firmware upgrade failed, and/or the Power LED is flashing.
The upgrade could have failed for a number of reasons. Follow these steps to upgrade the firmware and/or make the Power LED stop flashing:
• If the firmware upgrade failed, use the TFTP program (it was downloaded along with the firmware). Open the pdf that was downloaded along with the firmware and TFTP program, and follow the pdf’s instructions.
• Set a static IP address on the PC; refer to “Problem #1, I need to set a static IP address.” Use the following IP address settings for the computer you are using:
IP Address: 192.168.1.50
Subnet Mask: 255.255.255.0
Gateway: 192.168.1.1
• Perform the upgrade using the TFTP program or the Router’s web-based utility through its System tab.
15.My DSL service’s PPPoE is always disconnecting.
PPPoE is not actually a dedicated or always-on connection. The DSL ISP can disconnect the service after a period of inactivity, just like a normal phone dial-up connection to the Internet.
• There is a setup option to “keep alive” the connection. This may not always work, so you may need to reestablish connection periodically.
1. To connect to the Router, go to the web browser, and enter http://192.168.1.1 or the IP address of the Router.
2. Enter the password, if asked. (The default password is admin.)
3. On the Setup screen, select the option Keep Alive, and set the Redial Period option at 20 (seconds).
4. Click the Save Settings button.
5. Click the Status tab, and click the Connect button.
6. You may see the login status display as Connecting. Press the F5 key to refresh the screen, until you see the login status display as Connected.
• Click the Save Settingsy button to continue.
• If the connection is lost again, follow steps 1- 6 to re-establish connection.
16. I can’t access my e-mail, web or I am getting corrupted data from the Internet.
The Maximum Transmission Unit (MTU) setting may need to be adjusted. By default, the MTU is set at 1500. For most DSL users, it is strongly recommended to use MTU 1492.
• If you are having some difficulties, perform the following steps:
1. To connect to the Router, go to the web browser, and enter http://192.168.1.1 or the IP address of the Router.
2. Enter the password, if asked. (The default password is admin.)
3. Look for the MTU option, and select Manual. In the Size field, enter 1492.
4. Click the Save Settings button to continue.
• If your difficulties continue, change the Size to different values. Try this list of values, one value at a time, in this order, until your problem is solved:
1462
1400
1362
1300
17. The Power LED keeps flashing.
The Power LED flashes when the device is first powered up. Meantime, the system will boot up itself and check for proper operation. After finishing the checking procedure, the LED stays solid to show that the system is working fine. If the LED keeps flashing after this time, the device is not working properly. Try to flash the firmware by assigning a static IP address to the computer, and then upgrade the firmware. Try using the following settings, IP Address: 192.168.1.50 and Subnet Mask: 255.255.255.0.
18.When I enter a URL or IP address, I get a time-out error or am prompted to retry.
• Check if other PCs work. If they do, ensure that your workstation’s IP settings are correct (IP Address, Subnet Mask, Default Gateway, and DNS). Restart the computer that is having a problem.
• If the PCs are configured correctly, but still not working, check the Router. Ensure that it is connected and powered on. Connect to it and check its settings. (If you cannot connect to it, check the LAN and power connections.)
• If the Router is configured correctly, check your Internet connection (DSL/cable modem, etc.) to see if it is working correctly. You can remove the Router to verify a direct connection.
• Manually configure the TCP/IP settings with a DNS address provided by your ISP.
• Make sure that your browser is set to connect directly and that any dial-up is disabled. For Internet Explorer, click Tools, Internet Options, and then the Connection tab. Make sure that Internet Explorer is set to Never dial a connection. For Netscape Navigator, click Edit, Preferences, Advanced, and Proxy.
Make sure that Netscape Navigator is set to Direct connection to the Internet.


Frequently Asked Questions
What is the maximum number of IP addresses that the Router will support?
The Router will support up to 253 IP addresses.
Is IPSec Pass-Through supported by the Router?
Yes, it is a built-in feature that the Router automatically enables.
Where is the Router installed on the network?
In a typical environment, the Router is installed between the cable/DSL modem and the LAN. Plug the Router into the cable/DSL modem’s Ethernet port.
Does the Router support IPX or AppleTalk?
No. TCP/IP is the only protocol standard for the Internet and has become the global standard for communications. IPX, a NetWare communications protocol used only to route messages from one node to another, and AppleTalk, a communications protocol used on Apple and Macintosh networks, can be used for LAN to LAN connections, but those protocols cannot connect from the Internet to a LAN.
Does the Internet connection of the Router support 100Mbps Ethernet?
The Router’s current hardware design supports up to 100Mbps Ethernet on its Internet port; however, the Internet connection speed will vary depending on the speed of your broadband connection. The Router also supports 100Mbps over the auto-sensing Fast Ethernet 10/100 switch on the LAN side of the Router.
What is Network Address Translation and what is it used for?
Network Address Translation (NAT) translates multiple IP addresses on the private LAN to one public address that is sent out to the Internet. This adds a level of security since the address of a PC connected to the private LAN is never transmitted on the Internet. Furthermore, NAT allows the Router to be used with low cost Internet accounts, such as DSL or cable modems, when only one TCP/IP address is provided by the ISP. The user may have many private addresses behind this single address provided by the ISP.
Does the Router support any operating system other than Windows 98, Windows Millennium, Windows 2000, or Windows XP?
Yes, but Linksys does not, at this time, provide technical support for setup, configuration or troubleshooting of any non-Windows operating systems.
Does the Router support ICQ send file?
Yes, with the following fix: click ICQ menu -> preference -> connections tab->, and check I am behind a firewall or proxy. Then set the firewall time-out to 80 seconds in the firewall setting. The Internet user can then send a file to a user behind the Router.
I set up an Unreal Tournament Server, but others on the LAN cannot join. What do I need to do?
If you have a dedicated Unreal Tournament server running, you need to create a static IP for each of the LAN computers and forward ports 7777, 7778, 7779, 7780, 7781, and 27900 to the IP address of the server. You can also use a port forwarding range of 7777 ~ 27900. If you want to use the UT Server Admin, forward another port. (Port 8080 usually works well but is used for remote admin. You may have to disable this.) Then in the [UWeb.WebServer] section of the server.ini file, set the ListenPort to 8080 (to match the mapped port above) and ServerName to the IP assigned to the Router from your ISP.
Can multiple gamers on the LAN get on one game server and play simultaneously with just one public IPaddress?
It depends on which network game or what kind of game server you are using. For example, Unreal Tournament supports multi-login with one public IP.
How do I get Half-Life: Team Fortress to work with the Router?
The default client port for Half-Life is 27005. The computers on your LAN need to have “+clientport 2700x “ added to the HL shortcut command line; the x would be 6, 7, 8, and on up. This lets multiple computers connect to the same server. One problem: Version 1.0.1.6 won’t let multiple computers with the same CD key connect at the same time, even if on the same LAN (not a problem with 1.0.1.3). As far as hosting games, the HL server does not need to be in the DMZ. Just forward port 27015 to the local IP address of the server computer.
How can I block corrupted FTP downloads?
If you are experiencing corrupted files when you download a file with your FTP client, try using another FTP program.
The web page hangs; downloads are corrupt, or nothing but junk characters are being displayed on the screen. What do I need to do?
Force your Ethernet adapter to 10Mbps or half duplex mode, and turn off the “Auto-negotiate” feature of your Ethernet adapter as a temporary measure. (Please look at the Network Control Panel in your Ethernet adapter’s Advanced Properties tab.) Make sure that your proxy setting is disabled in the browser. Check our website at www.linksys.com for more information.
If all else fails in the installation, what can I do?
Reset the Router by holding down the reset button until the Power LED fully turns on and off. Reset your cable or DSL modem by powering the unit off and then on. Obtain and flash the latest firmware release that is readily available on the Linksys website, www.linksys.com.
How will I be notified of new Router firmware upgrades?
All Linksys firmware upgrades are posted on the Linksys website at www.linksys.com, where they can be downloaded for free. To upgrade the Router’s firmware, use the System tab of the Router’s web-based utility. If the Router’s Internet connection is working well, there is no need to download a newer firmware version, unless that version contains new features that you would like to use. Downloading a more current version of Router firmware will not enhance the quality or speed of your Internet connection, and may disrupt your current connection stability.
Will the Router function in a Macintosh environment?
Yes, but the Router’s setup pages are accessible only through Internet Explorer 4.0 or Netscape Navigator 4.0 or higher for Macintosh.
I am not able to get the web configuration screen for the Router. What can I do?
You may have to remove the proxy settings on your Internet browser, e.g., Netscape Navigator or Internet Explorer. Or remove the dial-up settings on your browser. Check with your browser documentation, and make sure that your browser is set to connect directly and that any dial-up is disabled. Make sure that your browser is set to connect directly and that any dial-up is disabled. For Internet Explorer, click Tools, Internet Options, and then the Connection tab. Make sure that Internet Explorer is set to Never dial a connection. For Netscape Navigator, click Edit, Preferences, Advanced, and Proxy. Make sure that Netscape Navigator is set to Direct connection to the Internet.
What is DMZ Hosting?
Demilitarized Zone (DMZ) allows one IP address (computer) to be exposed to the Internet. Some applications require multiple TCP/IP ports to be open. It is recommended that you set your computer with a static IP if you want to use DMZ Hosting. To get the LAN IP address, see “Appendix E: Finding the MAC Address and IP Address for Your Ethernet Adapter.”
If DMZ Hosting is used, does the exposed user share the public IP with the Router?
No.
Does the Router pass PPTP packets or actively route PPTP sessions?
The Router allows PPTP packets to pass through.
Is the Router cross-platform compatible?
Any platform that supports Ethernet and TCP/IP is compatible with the Router.
How many ports can be simultaneously forwarded?
Theoretically, the Router can establish 520 sessions at the same time, but you can only forward 10 ranges of ports.
What are the advanced features of the Router?
The Router’s advanced features include Advanced Wireless settings, Filters, Port Forwarding, Routing, and DDNS.
How do I get mIRC to work with the Router?
Under the Port Forwarding tab, set port forwarding to 113 for the PC on which you are using mIRC.
Can the Router act as my DHCP server?
Yes. The Router has DHCP server software built-in.
Can I run an application from a remote computer over the wireless network?
This will depend on whether or not the application is designed to be used over a network. Consult the application’s documentation to determine if it supports operation over a network.
What is the IEEE 802.11g standard?
It is one of the IEEE standards for wireless networks. The 802.11g standard allows wireless networking hardware from different manufacturers to communicate, provided that the hardware complies with the 802.11g standard. The 802.11g standard states a maximum data transfer rate of 54Mbps and an operating frequency of 2.4GHz.
What IEEE 802.11b features are supported?
The product supports the following IEEE 802.11b functions:
• CSMA/CA plus Acknowledge protocol
• Multi-Channel Roaming
• Automatic Rate Selection
• RTS/CTS feature
• Fragmentation
• Power Management
What is ad-hoc mode?
When a wireless network is set to ad-hoc mode, the wireless-equipped computers are configured to communicate directly with each other. The ad-hoc wireless network will not communicate with any wired network.
What is infrastructure mode?
When a wireless network is set to infrastructure mode, the wireless network is configured to communicate with a wired network through a wireless access point.
What is roaming?
Roaming is the ability of a portable computer user to communicate continuously while moving freely throughout an area greater than that covered by a single access point. Before using the roaming function, the workstation must make sure that it is the same channel number with the access point of dedicated coverage area. To achieve true seamless connectivity, the wireless LAN must incorporate a number of different functions. Each node and access point, for example, must always acknowledge receipt of each message. Each node must maintain contact with the wireless network even when not actually transmitting data. Achieving these functions simultaneously requires a dynamic RF networking technology that links access points and nodes. In such a system, the user’s end node undertakes a search for the best possible access to the system. First, it evaluates such factors as signal strength and quality, as well as the message load currently being carried by each access point and the distance of each access point to the wired backbone. Based on that information, the node next selects the right access point and registers its address. Communications between end node and host computer can then be transmitted up and down the backbone.
As the user moves on, the end node’s RF transmitter regularly checks the system to determine whether it is in touch with the original access point or whether it should seek a new one. When a node no longer receives acknowledgment from its original access point, it undertakes a new search. Upon finding a new access point, it then re-registers, and the communication process continues.
What is ISM band?
The FCC and their counterparts outside of the U.S. have set aside bandwidth for unlicensed use in the ISM (Industrial, Scientific and Medical) band. Spectrum in the vicinity of 2.4 GHz, in particular, is being made available worldwide. This presents a truly revolutionary opportunity to place convenient high-speed wireless capabilities in the hands of users around the globe.

What is Spread Spectrum?
Spread Spectrum technology is a wideband radio frequency technique developed by the military for use in reliable, secure, mission-critical communications systems. It is designed to trade off bandwidth efficiency for reliability, integrity, and security. In other words, more bandwidth is consumed than in the case of narrowband transmission, but the trade-off produces a signal that is, in effect, louder and thus easier to detect, provided that the receiver knows the parameters of the spread-spectrum signal being broadcast. If a receiver is not tuned to the right frequency, a spread-spectrum signal looks like background noise. There are two main alternatives,
Direct Sequence Spread Spectrum (DSSS) and Frequency Hopping Spread Spectrum (FHSS).

What is DSSS? What is FHSS? And what are their differences?
Frequency-Hopping Spread-Spectrum (FHSS) uses a narrowband carrier that changes frequency in a pattern that is known to both transmitter and receiver. Properly synchronized, the net effect is to maintain a single logical channel. To an unintended receiver, FHSS appears to be short-duration impulse noise. Direct-Sequence Spread- Spectrum (DSSS) generates a redundant bit pattern for each bit to be transmitted. This bit pattern is called a chip (or chipping code). The longer the chip, the greater the probability that the original data can be recovered. Even if one or more bits in the chip are damaged during transmission, statistical techniques embedded in the radio can recover the original data without the need for retransmission. To an unintended receiver, DSSS appears as low power wideband noise and is rejected (ignored) by most narrowband receivers.

Will the information be intercepted while it is being transmitted through the air?
WLAN features two-fold protection in security. On the hardware side, as with Direct Sequence Spread Spectrum technology, it has the inherent security feature of scrambling. On the software side, WLAN offers the encryption function (WEP) to enhance security and access control.

What is WEP?
WEP is Wired Equivalent Privacy, a data privacy mechanism based on a 64-bit or 128-bit shared key algorithm, as described in the IEEE 802.11 standard.
What is a MAC Address?
The Media Access Control (MAC) address is a unique number assigned by the manufacturer to any Ethernet networking device, such as a network adapter, that allows the network to identify it at the hardware level. For allpractical purposes, this number is usually permanent. Unlike IP addresses, which can change every time a computer logs onto the network, the MAC address of a device stays the same, making it a valuable identifier for the network.
How do I reset the Router?
Press the Reset button on the back panel for about ten seconds. This will reset the Router to its default settings.
How do I resolve issues with signal loss?
There is no way to know the exact range of your wireless network without testing. Every obstacle placed between the Router and a wireless PC will create signal loss. Lead glass, metal, concrete floors, water and walls will inhibit the signal and reduce range. Start with the Router and your wireless PC in the same room and move it away in small increments to determine the maximum range in your environment. You may also try using different channels, as this may eliminate interference affecting only one channel.
I have excellent signal strength, but I cannot see my network.
WEP is probably enabled on the Router, but not on your wireless adapter (or vice versa). Verify that the same WEP keys and levels (64 or 128) are being used on all nodes of your wireless network.
How many channels/frequencies are available with the Router?
There are eleven available channels, ranging from 1 to 11 (in North America).
If your questions are not addressed here, refer to the Linksys website, www.linksys.com.