Sharing internet from a Router to Switch

Question

We have a

• TP-Link (TD-W8951ND) Modem Router : Internet Connection from BSNL, India.
• D-Link DES-1024D 24-Port Switch : 16 Computers connected and we have a local site running which will be accessed from all these 16 computers. (IP Addresses ranging from 10.0.0.100 to 10.0.0.116. Computer IP from where we are serving the local site is : 10.0.0.100).

Now We want to share the internet connection to all the 16 computers.

What I already tried :

1. Used a crossover network cable to connect Router and Switch : Nothing happened. Moreover the lights either in the Modem or the Switch are not blinking.
2. Also tried with Normal network cable. But same as above. Nothing happened.
3. I checked the D-Link's switch manual and they wrote that it automatically detects crossover or something like that. But nothing happened in any of the above two steps.

Could you please suggest how I can proceed to make sure that all the above 16 computers can access the internet from the TP-Link modem? or at least any links to online resources.

Answer 1

You do not need a cross-over cable, a normal ethernet cable will do. The connection is the simplest you can imagine: draw a cable from any port on the D-Link switch to any switch port on the TP-Link modem/router. On the modem/router, there is one port right next to the antenna, on the back. Do not use this port, use any of the other four colored ports. Turn the router off, and then back on, there should be nothing else to do.

Answer 2

Unless your modem supports NAT/PAT (overload), you will not be able to have all 16 computers connect to the internet. This protocol is necessary to allow multiple hosts to communicate on the internet via your one public IP address. I highly doubt that your modem supports NAT though, so you will need to acquire any sort of router that performs NAT and has two interfaces.

As far as cables are concerned, you only need straight thru ethernet cables. Crossover cables used to be necessary for connecting similar devices (i.e. a computer to another computer or a switch to another switch).

Answer 3

This is almost identical to how my workplace's LAN is set up; your equipment should work well.

On your LAN, an internal private network, it doesn't matter how many IP addresses you use; it is the router's job to connect those with the on IP address that you get from your ISP. You can use 192.168.x.x or 10.x.x.x networks.

My recommendations and hints based on experience:
» Draw a diagram like mine. I walked around taking cell-phone pics of everything that used WiFi or an ethernet cable.
» As you update and change your hardware or cables, update the drawing. I made mine with free software Inkscape. Very easy to use.
» Set up DHCP on the router for the range of x.x.x.100 ~ x.x.x.199.
» See what the default IP address is for the 24 port switch; make sure this isn't the address of your router. Example: I use 192.168.2.x for my network and my Dell PowerConnect defaults to 192.168.2.1, thus I made the router/Gateway be x.x.x.2.
» Open up the DHCP devices list on your router and double check every MAC address to IP address.
» Save a spreadsheet of every computer's name, MAC address, and IP address as derived from your DHCP devices list.
» For every "static IP address" on your network, create a static entry for them in your DHCP server based on MAC address and then reset that computer/device to DHCP.

My current diagram as evolved from this original QA is a hybrid topology + physical location sketch: