shermstix

Okay, there have been a lot of questions about networking and many subsequent shoddy answers being thrown around. Therefore I give to you: The Home Networking FAQ! This is a very long read (7 pages in Word), so be prepared. There is a lot of good information.

Note: Every single scenario would be impossible to discuss in a single guide, seeing how MCSE takes at least 7 manuals that are 700 pages each, but basic home networking can be narrowed down to a few situations each of which can be customized for your specific purpose using the topics discussed below.

First we need to discuss basic networking topology.

• Workgroup - A workgroup is the most basic form of a network. Workgroups consist of a few computers that are tied together by some form of transmission line to allow transfer of data. Workgroups are mainly used in small home networks and special purpose situations. Workgroups are simple to setup and use, but provide no central method of administration.
• Domain - A domain is the enterprise form of networking. A domain consists of a centralized server(s) that has a few to a few thousand clients attached to the central server(s). Typically servers handle a multitude of tasks and run Network OSes like Windows Server 2003 or Red Hat.

Now that you understand the basic forms that networks can take, let’s discuss the devices that are used in the network infrastructure.

• NIC – A Network Interface Card is the most important device in the network. A NIC allows your computer to “talk” to the rest of the devices and computers on the network. You can create the most basic workgroup using only NICs.
• Crossover cable – A crossover cable allows two computers to directly communicate with each other through their NIC cards. This cable is created by swapping the 1&2 pins of a standard Ethernet cable with the 3&6 pins respectively. Do this on only one end to create the crossing of receive and transmit data. (standard Ethernet color scheme is: o/w, o, g/w, bl, bl/w, g, br/w, br)(crossover is: g/w, g, o/w, bl, bl/w, o, br/w, br).
• Hub – A hub is the most basic network device. It is simply an inter-connect for multiple computers to connect to each other. A Hub has no IP address and is unmanaged on its own. Hubs split bandwidth among all of the computers attached. If you have 4 computers on a network (A,B,C&D) with a 100Mb/s hub and A contacts B at the same time C contacts D, then you will split the connection speed between the two connections and effectively communicate at 50Mb/s.
• Switch – A switch is an improved form of a Hub. Rather than split bandwidth the way a Hub does, a Switch creates a direct connection between two computers when a connection is requested. So if you have 4 computers on a network (A,B,C&D) with a 100Mb/s switch, and A contacts B at the same time C is contacting D, both connections will have a full 100Mb/s connection.
• Router – A basic router is designed to allow communication between two different networks that reside on separate subnets. It works by striping away the MAC layer of a packet and inserting its own MAC address when a packet is forwarded. When the reply packet is sent back to the router, it strips its MAC address, reads the original IP address and inserts the associated MAC of the original client.

Okay, this covers the basics, now on to addressing.

• IP address – An IP address is the 32 bit number that is unique to each computer on a specific network. This is the primary way for PC’s to communicate on a network.
• MAC address – Media Access Control address is a hardware level number that is unique to every NIC in the entire world. Always a 12 digit number. This is how routers communicate.
• Subnet Mask – This is a 12 digit number similar to an IP address that tells a computer what portion of an IP address is the host ID and what portion is the network ID. For example, an IP address of 192.168.1.1 with a subnet mask of 255.255.255.000 would show that 192.168.1.x is the network ID and xxx.xxx.xxx.1 is the host ID.
• Default Gateway – This is the IP address of the device that is passing out IP address information on your network. Often the Default Gateway also provides internet access and DNS resolution.
• DNS server – A Domain Name Service Server is a device used to resolve Host names to an IP address. Fully Qualified Domain Names are used in your browsers so that you aren’t required to remember an IP address for each website you wish to visit. The FQDN is sent to a DNS server which in turn changes the name to an IP address and forwards the information back to your computer so you can create a connection with the website.
• WINS – Windows Internet Naming Service is what was used for windows networks to communicate prior to DNS. WINS resolves NetBIOS names to IP addresses in a similar fashion. This standard is old and is rarely used.

Alright, now that we understand the basic terms of networking, we can move on to the actual creation of a network. I will explain three basic versions of a network for home use and the basic settings required for each.

Basic network to share internet connection and data (no extra devices)

Materials: Active internet connection, 1 PC with two NIC cards(Primary), 1 crossover Ethernet cable, 1 more PC(secondary).

This is the most basic way to transfer files between two computers with minimal cost and effort. The reason this method is not as popular as the next method I will discuss later is because of security reasons. With your computer attached directly to the internet, it is wide open to any sort of attack. Windows XP Service Pack 2 helps to reduce this by including Internet Connection Firewall, but it is not perfect. So use this method at your own risk. With that said:

First ensure that the primary PC is able to connect to the internet. If you can not connect to the internet, ensure that your PC has the appropriate IP settings for your ISP. Click start>control panel>network connections. Ensure that your NIC is showing up as active (no big red X through it or it isn’t grayed out). If it is active, right click the connection and choose properties. From here you can set up a ton of options, but we are only concerned with the TCP/IP properties. Click Internet Protocol and click properties. This opens a window where you can set your IP information. If you are getting your IP information dynamically (like most ISP’s), then you just need to make sure that everything is set to “Obtain automatically”. If these are set correctly, click cancel and then cancel out of the LAN connections properties. If you still aren’t connecting, you might need to release and renew your IP information. Click start>run and type “cmd”. This opens the command prompt. From here, type ipconfig /release and press enter. Next type ipconfig /renew and press enter. This will force the ISP to give you a new IP address.

Now that you can connect to the internet, you need to get the other computer talking to the primary. This is done by connecting the second NIC on the primary to the NIC on the secondary. You might get an error saying that there is limited connectivity, but that is fine, we will address that in a little while.

Open up the network connections of the secondary PC and ensure that all of the IP options are set the same as the primary. Now you can setup the workgroup in one of two ways. You can run the “Network Setup Wizard” by opening network connections on the primary PC and choosing “Setup a home or small office network” Basically this automates everything from workgroup name to internet connection sharing. I strongly recommend this method, since it is easy and works very well. If you use the wizard, skip the next section. If you have issues with the wizard, continue with the following.

On the Primary PC, open up Network connections from the control panel and right click the second NIC (the one connected to your second PC). In the dialog box, choose the advanced tab. Check the radio button that says “Allow other users to connect through this computers internet connection.” Deselect the “Allow other users to control or disable the shared internet connection.” Now click okay. This will allow the primary computer to act as a router for the internet connection. You should now be able to browse the internet from the secondary PC. If not, you will have to renew the IP address on the secondary PC using the “ipconfig” utility as described earlier.

Next you will need to share your drives on the network, before you can actually send data between the two. Windows XP is highly customizable in this area, allowing you to share an entire drive, a number of folders or a single file. This is done by right clicking the drive/folder/file that you wish to share and choosing “sharing and security.” This opens a dialog and might give a warning “if you understand the risks but still want to share the root of a drive click here” (note, this will only show when you attempt to share an entire drive). Click on the warning and you will get the sharing tab to be fully functional. From here you simply click the “share this folder on the network” radio button, give it a shared name and choose “allow other users to change my files.” Now click okay. In order to share files between the two computers you will need to repeat these steps on the secondary PC.

Now that you have the drives/folders/files shared, you are ready to map your network drives. This can be accomplished a number of different ways, but I find it easiest to open “My Computer” and from the tool bar click “Tools” and choose “Map Network Drive.” This will open a small dialog box asking for the NetBIOS address of the share you want to map to. But who the heck can remember that? So just click “browse” and under the work group name you will find the name of all the computers in your workgroup as well as the resources they are sharing. Here you just click the drive you want to connect to and choose okay. Ensure that the “Reconnect at login” button is checked and click okay. Now the mapped network drive will show up in you’re my computer every time you start the computer. You can simply drag and drop files, as you would if this were a drive inside of your PC.

Basic network to share internet connection and files using a router

Materials: Consumer router, 3 Straight through Ethernet cables, a Primary PC with one NIC, Secondary PC with one NIC.

Note: I suggest this method for those wishing to share a cable broadband connection or those with DSL who plan to bridge their modems. DSL modems typically have a router built into them, so some connectivity issues can be had if you attempt to directly attach a DSL modem to a consumer router without bridging it. I will not discuss bridging here, but you can find the necessary guides for your particular modem using Google. I would suggest that those who are using DSL just purchase an unmanaged consumer switch and use it in place of the router. The only difference will be that the switch has no real configuration options aside from MAC tables, which aren’t generally configured in an unmanaged version. With that said here we go.

Consumer Routers have become ever so popular in the last few years, since prices have fallen dramatically and Windows XP has made home networking a breeze. A router also provides a hardware level firewall between you and the rest of the internet, so even with basic settings you will have a highly secure connection. The problem is that there are so many product choices, what do you look for? My suggestions are to stick to the big names. D-Link, Linksys and Netgear are the most popular routers because they are highly reliable and easily configured. For the most part, you can pull them out of the box, plug them in and they work flawlessly. I am very partial to D-Link, because their interfaces are standard across devices, they have wizards for the newbies and advanced options for those who wish to customize their connection. My directions will be based on the D-Link DI604, but can easily be adjusted for whatever router you purchase since technical terms are all the same.

First you will need to make sure that your internet connection is up. If everything is good on that end, start by plugging an Ethernet cable into the WAN link on the router and connecting the other end to the cable modem. Now power up your router. You will see a bunch of lights flash and it run a few tests. It will then show the WAN link as active on the front of the router. Next, connect one end of an Ethernet cable to the NIC on your primary PC and the other to port 1 on the router. You should get an activity light for port 1 on the front of the router. Your Primary PC should automatically start to negotiate an IP address from the router. Once your network address is acquired, you should be able to browse the internet. If not, it will be taken care of momentarily. Repeat those steps for your second PC. Everything should be identical, but for port 2 on the router. Now, on each computer, open the command prompt (start>run>type cmd>press enter). Type “ipconfig /all” and press enter. Look for the NIC that is connected to the router and write down the 12 digit number listed beside Physical Address as well as the Host Name for your computer. You will need these later.

Open your browser on the primary PC and type 192.168.0.1 into the address bar and press enter. This will open a password authentication dialog. Type “admin” for the user name and “password” for the password, make sure that the save password box is NOT selected and choose okay. This will pull up the router options list that allows you to configure many options. The first thing to do is setup a new password for your router. This is found under the admin/tools menu. You can change it to anything you like, just make sure you don’t forget it. D-Link includes a quick start guide with a place for this information. Use it!! Once you set the new password, ensure that remote management is disabled and choose apply. The device will reset and you will need to log in again. Under the WAN setting if you use cable internet you should ensure that Dynamic IP address is selected. If you use DSL, choose PPPoE and enter in your information. You should also clone your MAC address by using the options at the bottom of the menu. Click apply and then go to the DHCP menu. Click the Home tab. From here you can specify the range of IP addresses that your router can hand out. For security reasons, set the router to only hand out 10 addresses. So just change the last three digits in the start IP to 100 and the last three in ending to 110. Ensure that the lease time is set to 1 week and click apply. Next click the Advanced tab. Here is where you will need the MAC and Host Name information from earlier. Click the MAC filter Radio button. Now choose the “allow only computers with the following MAC addresses listed below to access the network.” Here, you will enter in the Host Name into the name box, enter the 12 digit MAC address for that host and choose apply. This essentially is all you will need to do to fully configure your router for top security.

At this point you should be able to browse the internet on both computers. If not, you will need to ensure that your computers are setup to receive DHCP and DNS information dynamically by opening “Network Connections” from the Control Panel in Windows. Now right click the NIC card that you are working with. Choose properties. Click the Internet Protocol option and click properties. Ensure that “Obtain an IP address automatically” and “Obtain DNS information automatically” are both selected. Click okay and okay again. If you still can not browse the internet make sure that your cables are not faulty, your NIC is working and your ISP is functioning.

The final steps are to setup resource sharing between the two computers. This is done in a fashion exactly the same as the previous network setup. The only real difference between this network and the more basic one is the use of the router.

Extra Information:

With either of these networks you can setup print sharing, so that you could attach a printer to your primary computer and print from the secondary. The only limit is that your primary PC would have to be turned on for the printer to receive the information. The only way around this is to use a print server, but that adds to the cost of the topology. To configure printer sharing, make sure that your network is fully functional. Open the “Printers and Faxes” utility from the control panel. Right click an empty space and choose “add a printer.” Now you will choose Network printer, click next and choose browse. Browse the network for the shared printer (which is done automatically when you have a workgroup). Click the printer, choose okay and finish the wizard. You Windows will automatically pull the printer driver from the primary PC and install it on your secondary computer. You will now be able to print from the secondary computer!

Wireless Internet connection

Wireless home networking has become an ever popular option among many people. The problem is that most individuals don’t understand how to secure their network and defeat the purpose of having a Firewalled router to begin with. Basic setup for a WiFi router are exactly the same as for a wired router with the only difference being the options that you would set for the WiFi in the router and on your Wireless NIC. The WiFi router will come with a very detailed instruction manual. I suggest you read it from front to back. Inside you will see every option that you need to configure. I will go over the main ones that you need to ensure you configure for maximum security.

• SSID – Secure Server Identification. This is your network ID and is used like a user name when logging onto a network. You need to change this from the default of “linksys” or “DI624” that most routers come with. Change it to something difficult to guess, integrating numbers and letters into the ID. Example would be DellSucks written as “d31L5uCk5”. You get the idea. Also make sure that you don’t broadcast your SSID, or you defeat the purpose of changing it since anyone will be able to see it.
• Enable WEP or WPA. You need to have at least WEP enabled. Make sure that you use a very random key and that you use the maximum amount of numbers available to you. There are many WEP key generators on line and some routers even include them in the options. WPA uses a different method of shared secrets that are a little more complex, but still easily configurable using the manufacturers supplied directions.
• MAC filtering. As discussed earlier, MAC addresses are unique for each NIC card that is ever created. If you filter based on MAC, only computers with the correct MAC address can connect to your network.
• Change your WEP key /WPA secret at least quarterly. Every three months think of a new key or secret and use it. That way if someone does crack your security without you knowing, they will have to start over when you change it.

WiFi is inherently unsecure, but following these steps will ensure maximum protection. Only the most determined hackers will be able to breach your network.

Whew, that was long in the making, but I am sure that many headaches will be solved because of this guide. Hope you enjoy reading it as much as I enjoyed making it. If you have any further questions don’t hesitate to PM me, ask in this thread or start a new one.

Chopes

love it. +REP

somody

great FAQ lots of effort went into this...put a warning (long read, dont let it distract u) at the top in red rep++

shermstix

Added the Warning. It is long and took me quite a while to develope. I had been planning on it since December of Last year, but got side tracked and then kept putting it off. I am glad that everyone has enjoyed it thus far.

somody

i'm glad...it's really good!

johndoe

just wondering but does the crossover cable work if you have dial up and 2 pcs with NIC cards? very nice!

somody

johndoe:

for more information visit:

Sharing a 56K Connection.

this is a good guide!

DataX

Nice faq, basics of networking, and networking under windows... How about a faq on IPMASQ under linux? I'm pretty confused on that, and maybe some other people too.

shermstix

Yes Johndoe, the crossover cable will work with a 56K modem and 2 NICs. You would have to have the PC with the 56K modem turned on for the dialup connection to be initiated though. This can be done using demand dialing, but I don't have time to go into it here. As for the Linux guide, I don't know much of anything about Linux, so I really couldn't be of service in that department.