Connecting a switch through a router

I have a router connected to my cable modem. Then I have a switch connected to that router. I have computers connected to the switch. When I look at the list of connected devices on the routers control panel it doesn't show anything past the switch. I have already checked all of the cables and they are all good. Other than that I don't even know where to start looking for the problem. I figured once I got it all plugged in it would just work.

CaseyB

Posted 2011-07-06T00:14:34.720

Reputation: 203

Are your computers configured to use DHCP? – Flimzy – 2011-07-06T00:22:23.407

A very similar question was asked earlier today. Is this you? http://superuser.com/questions/306760/routing-to-a-computer-on-a-switch-behind-a-router

– Spiff – 2011-07-06T00:36:43.097

Is your worry just that the router's web UI isn't showing the computers, or are those computers actually unable to get Internet access via setup? – Spiff – 2011-07-06T00:53:05.123

What model router? I would like to see the ports on the back by looking it up. What model switch? – KCotreau – 2011-07-06T01:00:58.193

@Flimzy Some of the computers are, some use static IP's. @Spiff, Nope, not me. My worry is that is wasn't working. @KCotreau, They are both Netgear. – CaseyB – 2011-07-06T13:27:49.837

Answers

Depending on where you're looking and the age of the equipment, I can think of two good possibilities:

1) Your switch and router are not "Auto Uplink" capable, meaning that you would need to use a crossover cable to patch them (normally yellow, the green and orange pairs are reversed).

2) If your switch was powered on when your router fired up, your computers would fail to get a DHCP lease, and so would not be listed on the DHCP server's connected hosts list.

Bryan Agee

Posted 2011-07-06T00:14:34.720

Reputation: 367

The router and switch are both less than a year old. I tried shutting down and restarting them in every imaginable order. As a last ditch effort I replaced both ends on the cable connecting the two and that fixed the problem even though the cable tester said it was good! – CaseyB – 2011-07-06T13:45:22.147

-1

Your router likely is only intended to route through to a single ethernet port. Does the ethernet port you're connecting your switch to have "LAN" written on it? If so, then you may still be in luck. Otherwise, it sounds like you're still actually in need of a router, that provides a LAN port.

Seems most routers out there have integrated switches and so for those you can just run an ethernet line to another switch and they magically work out traffic routing for you.

I suppose another little thing to keep in mind is if you're dealing with damaged cables, that'll kind of jam a stick in your spokes.

James T Snell

Posted 2011-07-06T00:14:34.720

Reputation: 5 726

Hey! Who was that with the down vote!? Meet me at the flag pole at noon. – James T Snell – 2011-07-06T00:34:04.363

1Even if a router only has a single Ethernet port, plugging a switch into that port should never be a problem. Routing and switching happen at two different layers, and shouldn't have any effect on each other. – Spiff – 2011-07-06T00:34:36.530

I agree it shouldn't be a problem. But there is some fairly silly legacy hardware out there my friend.. I see nothing inherently flawed in asking the asker what the port is actually labeled. – James T Snell – 2011-07-06T00:42:18.990

It's not just your question about how the port is labeled. The second paragraph of your Answer also shows that you don't understand the difference between layer 2 (switching) and layer 3 (routing). – Spiff – 2011-07-06T00:56:52.360

It does? Explain please, with crayon illustrations (preferably scented ones). – James T Snell – 2011-07-06T00:58:34.247

And look at that, the problem ended up resolved by trying a different network cable... He had a stick in his spokes afterall. – James T Snell – 2011-07-06T16:00:25.150

In all fairness I did check for said stick first and didn't see one! – CaseyB – 2011-07-06T22:43:03.993

@CaseyB Indeed, technological sticks can be sneaky. With their ambiguity and all ;) – James T Snell – 2011-07-06T22:48:36.983