Problems with a switch connected to my airport

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Problems with a switch connected to my airport

Ok, This one has me pulling my hair out. It just doesn't make sense. My setup is as follows >TWC Router (motorola surfboard)> Airport extreme 2014> Ethernet cable from airport to basement>Switch> MBP. The signal coming from the airport upstairs is fine. If I plug my MBP into the ethernet cable in the basement I instantly get an IP and connectivity. When I try to access the connection via an ethernet cable coming out from the switch I get a self assigned IP and no network connectivity. Thinking the switch may be junk I took the switch to work using the same ethernet cable I used from the switch to the MBP and the switch worked flawlessly. Thinking maybe my airport got a little confused handing out IPs - I reset the router completely and started from scratch. Same result. So the switch is fine - so are my cables. I can't for the life of me figure this out! My airport is running the latest firmware and other than this issue has been working just fine. Any help would be immensely appreciated!

MacBook Pro, OS X Yosemite (10.10.4)

Posted on Jul 2, 2015 6:24 PM

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Answer 1

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Bob Timmons

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Jul 2, 2015 7:35 PM in response to allstyle777

Temporarily, connect a short spare Ethernet cable that you know is working to one of the LAN <--> ports on the AirPort Extreme. Go ahead and check with your Mac to make sure that it can get a good connection this way.

If it can, temporarily move the Ethernet switch and connect it to the same short Ethernet cable that you just used with the Mac. Now test using another short, spare Ethernet cable from the switch to the Mac. Check each port on the switch, if possible.

Does that Mac get a good connection that way?

If yes, you know the switch is working and Mac is working.

Connect the switch again directly to the long Ethernet cable and try again. If the Mac won't connect that way, you likely have a wiring issue in the long Ethernet cable.

A Mac connected directly to a mis-wired cable will still usually work....at reduced speeds......so you may be thinking that the Ethernet cable is "working" when it is possibly not wired correctly.

Some switches will try to compensate for a mis-wired cable and some will not. Some will try, but are not successful. That might be your issue. If it is, you will need to rewire the Ethernet plugs on the long cable at both ends.

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Answer 2

allstyle777 Author

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Jul 2, 2015 8:00 PM in response to Bob Timmons

Great suggestion Bob, I did that and sure enough everything worked upstairs directly from the airport. And then from the airport to the switch. Everything worked perfectly. This narrows it down to the cable running from upstairs downstairs. Did a remodel recently on the house and burried a ethernet cable behind the wall. Long story short, when made the cable I left one end upstairs untouched - and the end downstairs I had to crimp on myself. I used a cable tester and all of the wires matched up on the tester... I mean by process of elimination the cable has to be the issue but I am perplexed what to do next. Should I re do both ends of the ethernet cable running upstairs and downstairs? I used the basic vanilla wiring diagram here: http://sburke.eu/blog/wp-content/uploads/2010/10/Ethernet-Network-Cat5e-Cable-56 8b.gif

Is there some other configuration I should use? Thanks again!

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Answer 3

Jul 2, 2015 8:13 PM in response to allstyle777

I used a cable tester and all of the wires matched up on the tester...

It's really hard to find a reasonably priced tester that is really accurate. I've bought at least 3-4 "testers" that were worthless. They said that just about any cable was "good" when I knew it wasn't.

Should I re do both ends of the ethernet cable running upstairs and downstairs?

Yes. The T-568B standard is what you want.

Hopefully, when you buried the cable behind the wall, it did not kink, or a nail did not find its way through the cable.

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Answer 4

allstyle777 Author

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Jul 2, 2015 8:14 PM in response to Bob Timmons

I will redo the cable when I can borrow the tools from work again, and I will post the results. I guess my problem was that I assumed the cable to be good based on the tester saying it was, as well as my MBP connecting with it. Live and learn! Thanks again for the tip I don't know if I would have thought to question that cable on my own.

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Answer 5

allstyle777 Author

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Jul 7, 2015 4:03 PM in response to Bob Timmons

So - this one took me awhile but with you pointing me in the right direction I was able to get it. I had 1 wire out of place in the diagram on one of my ends- for some reason my cheap 10 dollar tester said it was ok but alas it was not. I guess my mac was able to correct my error - but my cheap gigabit switch was not. Thus my issue. Switch is happy, xbox is happy, I am happy. Networking generally tends to give me headaches but after a week or so of frustration- I actually learned something! Thanks again for your help!

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