Multi-computer connection LAN via Ethernet

Question

Our teacher gave us 4 PC's at school . I want to setup a LAN connection between them all for file sharing via Ethernet cables, and no internet access is available or needed. I have successfully connected the first two with a simple cross-over cable, but I am lost on how to connect all 4. Because I won't use internet, I assumed that I won't need a modem either, am I wrong?

1. Should I use a modem/router?
2. How do I? Without internet, that is.

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EDIT:

So according to what Paul said, I should just plug in the Ethernet into the hub/router, but all the computers tell me that the cable is not connected, while on the hub I see that it has not detected the computer either.

In short, the devices are only detecting the cables.

Note: Each PC has one NIC

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EDIT 2

The router is on, but shows no response at all. But I think it is wrong setup. I just connected to power, but someone told me that I need a telephone cable into the wall even if no internet is needed.

Answer 1

You won't need a modem but you will need a (cheaper) device called a hub or switch. For your purposes a router is a more sophisticated device than you will need, but it should also work.

Plug a cable from each pc to the hub/switch/router. Usually it would be a straight patch cable, not crossover (aka twisted), but most hubs/switches/routers will auto-sense and work with whatever you plug in.

Answer 2

There are multiple possible answers to this. But let me start with one basic part. If you only have one NIC per computer then you need a device to connect all four to. This is called a switch. Many 'modem' and 'routers' are in fact multiple devices in one box. The four ports on the LAN side usually act the same as a regular cheap switch.

You then have this setup:

                    [switch]
                   |  |  |  |
                  /   |  |   \
                 /    |  |    \
       Computer 1     C2 C3    Computer 4

To connect an end device (the computer) to a switch you use a normal ethernet cable.
To connect two similar device (PC direct to another PC, or switch to switch) you would use a crossover cable.

Note that most modern switches include auto MDI/MDX and will auto matically compensate for the wrong cable. As do all gigabit switches.

Lacking a switch or a device which includes a switch you can do something with at least two network cards in each PC, forming a ring. Or one network card per other PC (so 3 NICs per PC in this case). This post shows a nice diagram on on how that was done with 3 PCs. (Ignore the internet part).

I mention that for completeness sake. This is not something you will need in most cases.

That answers the part about the physical connection.

Net up if the configuration. How you do that depends per OS, but assuming TCp/IP you want to give each computer a different IP address. And since you want them to communicate give them an IP in the same network range.

The easiest way for a small setup is to do that manually. E.g.

• On PC 1 set IP 10.0.0.1 with netmask 255.255.255.0
• On PC 2 set IP 10.0.0.2 with netmask 255.255.255.0
• On PC 3 set IP 10.0.0.3 with netmask 255.255.255.0
• On PC 4 set IP 10.0.0.4 with netmask 255.255.255.0

That will put all PCs in the network part 10.0.0.x. They can talk to eachother. You are done.

Alternatively you can set up a DHCP server on one of the PCs or on a 'very capable switch' (read: a SOHO router will do) and set all the PCs to DHCP. This means the PCs will ask there network to give them all the needed information. You will have to put the answers to this in the DHCP servers configuration.

The latter is more work and for a simple setup I would skip it. But it scales a lot better and when you get to dozens of PCs this is the way to go.

Lastly, read this post on our sister site serverfault. It explains a lot of the background.

Answer 3

You need to use a switch / router. Hub are last centurie's things. Each PC should be connected to the switch with a straight cable.

Then you have to go to network connection and set static IPs for all the 4 PCs in the same network. Check this (bad source, but simple enough concept) to see what's a subnet. You may need to disable Windows firewall too.

BTW: Modern NICs do not need crossed cables to connect two PCs anymore, they negotiate and configure their NIC's ports properly.

Answer 4

1. Check your lan cards and cables on workability.

   a. Check that your LAN connection actualy works on all PC, connect each one of them between each other(if you have that much time to test 100% connection is ok)

   b. Check your LAN configuration on each PC, so they must be in one network and share same mask example IP: / example MASK:

   192.168.0.101   255.255.255.0
   192.168.0.102   255.255.255.0
   192.168.0.103   255.255.255.0
   192.168.0.104   255.255.255.0

   no DNS or gateway needed

2. Then plug all of the LAN cables from PC's to the switch/hub (most modern switches do not care how you cross patch your cables as long as they are the same in configuration)

OR

You can do steps 1 and 2 then put all cables into ROUTER, after that configure router to enable DHCP on it and set all your LAN configuration on PC's to Auto.

If there are still problems and your 1 and 2 steps are ok, see that you OS configuration with network has shared files enabled for local network (Its home network for XP and W7)