Lose internet when plugging into switch

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Level 1

21 points

Lose internet when plugging into switch

I am perplexed why I can create a wireless network with my airport extreme and have great internet connectivity through my cable company, but when I plug the airport into a switch to distribute the internet through out my office the internet immediately starts slowing down and eventually completely goes away. Unplug extreme from switch and the internet comes back for wireless clients. Problem started about a month ago. I figured switches were going bad so I replaced every switch in the office. Did not solve problem. Thought maybe airport extreme was going bad so I replaced it with latest airport extreme (cube). Problem still exists. Nothing has changed in my network configuration in past two years. No other services that use the network is effected, just internet connectivity. I was quite ugly with my internet provider thinking it was a service issue until on a whim I unplugged extreme from switch and my iPad, iPhone, and macbook pro were able to connect to the internet wirelessly instantly. Plug it back into the switch and internet connectivity for wireless and wired goes away.

Any suggestions are greatly appreciated.

Posted on Jan 3, 2015 5:53 PM

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Answer 1

John Galt

Level 10

155,690 points

Jan 3, 2015 9:13 PM in response to jedicpa

What you describe will occur if you inadvertently connect the switch to another device's WAN port, or if packets are otherwise caused to endlessly circulate back to their origin. This overloads a network quickly, since it will soon have time to do nothing else.

A simple oversight that occurred when you replaced all the switches at once is the likely cause, but it's about as difficult to envision your network topology as it is to describe it in words. Start by examining exactly what is connected to the switches until you find the improper connection. If you have no idea where to start, remove all the switches from the network, then connect one device to one switch, make sure it works, then connect the next one, and so forth.

If you were wondering how to spend your time this weekend, now you know.

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Answer 2

Tesserax

Level 10

158,094 points

Jan 3, 2015 9:21 PM in response to jedicpa

Just to be sure I understand, do you have an Ethernet switch connected to an Internet modem, and then, have the AirPort Extreme connected to the switch ... so your network configuration would look something like: modem > switch > Extreme?

... or is it: modem > Extreme > switch? How many other switches do you employ in your network and how are they connected?

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Answer 3

jedicpa Author

Level 1

21 points

Jan 4, 2015 4:25 AM in response to Tesserax

cable modem> wan port AE> lan port AE>switch

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Answer 4

jedicpa Author

Level 1

21 points

Jan 4, 2015 4:28 AM in response to John Galt

Thanks for the suggestion. Besides the AE itself I am trying to think of a device that even has a wan port in the office. I have 10 macs, 4 voip phones, and 3 network printers. I don't think any of those devices have a wan port.

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Answer 5

John Galt

Level 10

155,690 points

Jan 4, 2015 7:01 AM in response to jedicpa

That's only one explanation, and an oversimplified one at that. In any event I think your best course of action might still require disassembling your network and adding one piece at a time. Assuming your business is closed for the weekend, now might be your best opportunity.

Short of that, power down all switches, Macs, other devices (though I doubt iPhones, voip phones or printers can contribute to the problem) and the Extreme (no need to reset it). Then, power up the Extreme and one Mac that is connected through a switch. Turn Wi-Fi "off" to ensure Ethernet is its only viable network connection, as well as for troubleshooting simplicity.

It should have no connection until you power up that switch. Do that, and determine if the problem still exists.

Assuming it doesn't, turn its Wi-Fi back "on" and test.

The iPhones and iPads should also be working at this point.

Proceed to the next Mac and test the same way. If it's connected to a different switch, power it on also, then re-check the first Mac.

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