Can't connect desktop to INternet via Netgear GS105

Hi,

I think you still misunderstand this. The router's WAN port should connect the modem. The switch and other devices should connect to the router LAN ports.

Sathaye wrote:
Ok thanks! So looks like for my setup I will need to have a modem with atleast 2 ports. One for the switch and another for the router

We're falling into the trap of the XY Problem. We're discussing solutions that don't really make sense or are strange but we're not even sure what problem you're trying to solve.  It might help for you to state your problem. To save one more round of back and forth, I am going to guess what it is. Please make any corrections.

Problem Statement

You want Wi-Fi towards the back of the house but you have at least one wired computer at the front of the house, which is where your modem is located.  Your modem is a pure modem (i.e. it has no built-in router).

Your proposed solutions

1. Put the router at the back of the house and wire it and your computer to a switch. Wire the switch to the modem.
2. Alternatively, get a 2-port modem, which will allow you to connect both your computer and router in a similar manner.

A digression: What is a router

What we call a router in the home networking market is actually an amalgam of several devices, which, in theory, can exist separately (and they often do in business networks):

• A firewall to block unwanted traffic arriving from the Internet
• A Network Address Translator (NAT) to share the, typically, one IP address provided by your ISP with all of your devices
• An Access Point to provide Wi-Fi service
• A DHCP server to assign IP addresses to devices connected to the LAN or Wi-Fi
• An Ethernet switch for wired devices
• And a router to connect different IP networks together (specifically, the home IP and ISP networks).

In recent years, vendors have also added other functions, such as a print services, media sharing and USB drive sharing, but these are not relevant to the discussion.

Issues with your solutions

I explained previously that nothing should go between the modem and the router. From the above, it should now be clear why. If you put a computer on the "Internet" side of the router, it will be outside the firewall, so it won't be protected. The router won't assign it an IP address because the DHCP server only assigns IP addresses to devices connected to the router's LAN or Wi-Fi. ISPs only provide you with one IP address. If your computer were to grab it, well, tough luck to your router and all devices behind it. If your router grabs it, then your computer has no Internet access. This is why your computer couldn't get an IP address with your original setup.

There are some modems with 2 Ethernet ports. The new DOCSIS 3.1 cable modems, for example, have these but the dual Ethernet ports are for link aggregation. They dont have a built-in router, so you will have the same issues as above. Things will work if there is a built-in router. This is one of the solutions, below.

Solutions

There are a few ways to solve the problem, as I have stated.

1. Connect the router directly to the modem. Run a wire from the router to the computer. You probably didn't want to do this because you would have had to run two Ethernet cables from the front to the back of the house.
2. Move the router to the front of the house. Connect the computer to it. Install a Wi-Fi Access Point in the back of house and wire it back to the router. Bonus, you will have Wi-Fi coverage in the front and back of the house.
3. Replace the modem with an all-in-one modem/router.  Connect the computer to it. Repurpose your existing router as an Access Point.  Remember that's one of its functions, and you can actually disable/bypass the firewall, NAT and DHCP server functions in a router. Same bonus as #2.
4. Remember when I mentioned that for the vast majority of people, the setup should be modem->router->switch->devices?  Well, there is a way to put a switch between the modem and router. You have to use a managed switch and a router that supports VLANs. I won't go over the details because it's an advanced technique that can be tricky to set up. It's also slightly suboptimal because traffic for your computer will have to travel twice between the switch and router.

Again, I have made a guess at what your real problem is (i.e. the X in the XY Problem). If my problem statement is incorrect, then we'll have to start over.