this post was submitted on 29 Nov 2023
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Home Networking

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I'm unclear on the purpose of a router. Could I just have a cable modem directly connected to a (smart managed) switch that feeds all the clients?

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[–] 1sh0t1b33r@alien.top 2 points 11 months ago

Your router routes. It also assigns IP addresses to devices. So no, you can't just connect a switch to a modem and be Online. It may be possible if your ISP gave you multiple IP addresses and you set them static to your devices, but you also do not want your private devices directly on public Internet.

[–] OtherTechnician@alien.top 2 points 11 months ago

In most residential service, the ISP configured the modem to provide a single public IP address. Besides serving as the point of connection to the modem, a router serves a few critical purposes:

  1. Provides a firewall to protect your network from malicious intrusion attempt from the Internet

  2. Provides the needed DNS and DHCP services to devices on your network that allows them to have an IP address and the ability to find external sites

  3. Manages the IP address translation and routing required to allow all of your network devices use a single public IP address

If you connect your modem directly to a switch that connects to your network, the first device that requests an IP address will get the single available IP address and none of the others will get a usable IP address and as a result, will not be able to access the Internet. They also will be lacking the services provided by a router as listed above.

Please get a router!

[–] Ariquitaun@alien.top 1 points 11 months ago

No, because a switch can't route traffic from one point to another. Specifically, it can't do NAT. Without NAT you can only have 1 device connected to the internet.

[–] ShaMana999@alien.top 1 points 11 months ago

You need something to manage your clients on that network. If your modem can do that, good, you may not need a router. If the modem can't or it is not setup-ed and you can't access it, then you most likely would need one.

[–] Haelios_505@alien.top 1 points 11 months ago

Technically possible with a layer 3 switch but routing is still required and best done with a purpose built router.

[–] ycdrtt@alien.top 1 points 11 months ago

A modem modulates/demodulates. A router routes

Most modems these days are combined with a router. So yeah you can use the routing capabilities and plug into a smart/dumb switch and it will work

[–] Objective_Reference@alien.top 1 points 11 months ago

thanks for all the replies. very helpful

[–] tgreatone316@alien.top 1 points 11 months ago

Unless you have purchased a VERY large block of external routable IPs, no. Your devices would have no idea how to get out to the rest of the world. Also, I know some switches can also route, but then they are essentially routers.

[–] IlTossico@alien.top 1 points 11 months ago

Yes you need one. And the world Router is self explanatory.