Macbook won't connect to Internet over long cable?

I have a baffling problem I hope someone has a solution to:


My setup: cable model to Apple AirPort router. (This question has nothing to do with the wireless capability of the AirPort router.)


When I plug my Macbook One into the Air Port router ethernet port via a short 3 foot Cat6 cable it works fine: Comes up with IP 10.0.1.13 and has Internet access.


When I plug the same laptop to the same router port via a longer Cat6 cable it doesn't work:


It returns IP 169.254.246.97 and the laptop says: Ethernet has a self assigned IP address" and NO internet connectivity.


I have tried 4 different long cables all of which have been tested with a cable tester for continuity and pin assignments (straight through). All cables were installed at the same time and are probably 100 to 125 feet long but far less than the 300 foot (100 meter) recommended limit.


And here's the real clincher: One of them has been working fine and connects a Tivo to the Internet for updates as well as streaming Netflix and Amazon video with NO hiccups so I "know" it connects to the Internet from the TIVO.


So, why can't my Macbook connect over the longer cables (like the TIVO does) and why is it coming up with a different self assigned IP address when connected via the longer cables?

MacBook, Mac OS X (10.6.8), iPhoto

Posted on Jun 15, 2015 3:15 PM

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13 replies

Jun 15, 2015 3:58 PM in response to Nexsen

Ethernet speed negotiation can be one problem.


What OS is the Mac running .. you have snow leopard on the profile.. and how old is the Mac??


What model is the airport? A1xxx from the base please.


In the network preferences of the Mac go to the advanced of ethernet.


Turn IPv6 to link local only.. just while you are there.


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Now click on hardware.


If there is no connection you will see this has no connection.. force it down to slower speed.


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Test on 10baseT full duplex.. and if that works try 100baseTX full duplex..


If all of them fail, then the port on the laptop is failing. (but the cable might not be capable of gigabit.. TIVO will only have 100mbit..).

Jun 16, 2015 1:16 PM in response to LaPastenague

Thanks so much! I was able to connect at 10 Base t (10M) only when manually forcing it.


Oddly 100M doesn't connect but as I mentioned the Tivo Roamio works fins so it may be negotiating down to 10M too I suppose.


Here is the data you requested:


OS is 10.6.8 on one of the first Macbooks (Macbook 1.1 with 2 GHZ Intel Core due)


The AirPort is an old A1143. I have a new Air Port but had to switch back to the old one because the range was too low for the old Macbooks. Apple says to buy new Macbooks but we have a couple that are only used for email and occasional Internet browsing so we can't justify replacing them.


I was actually using the Macbooks to test a problem I was having with another device and discovered the same problem on the Macbook. The manufacturer of that product says they negotiate and use either 10 m or 100M but clearly their product does the same thing the Macbook does and failes to (AUTOMATICALLY) negotiate 10 M.


Is that something peculiar to the old Air Port router? To work when MANUALLY forced to 10M but not to be able to negotiate 10M automatically.


I would also be surprised if all 4 of my cables (CAT6 about 125 feet long) are incapable of 100 Mbit and only work at 10Mbit.


Can you recommend a good wireless router that works well (good range) with the old Macbooks and might solve these other isues.


As mentioned I have the newest Apple Air Port router but had to remove it since it had dismal range for the old Macbooks. And by dismal I mean it wouldn't connect to a laptop 20 feet away (through a brick wall however) with an Apple range extender (the little wall wart thing I forget the name of) less than 5 feet on the other side of it. The old router connects fine through the same range extender. I can't afford for that to stop working.


Thanks again for such a great answer and if you have any other suggestions on how I might get that other device to connect over the long cable let me know.

It supposedly is negotiating for 10 or 100 M but I have no way to force it to use 10 as you showed me how to do on the Macbook. I need for that negotiation to work and can consider another router.

Jun 16, 2015 3:05 PM in response to Nexsen

The AirPort is an old A1143

That is very old and they confused the world by issuing two of them with the same model number but different part numbers.. the first has 10/100 ports and the second was identical but upgraded to gigabit. In the airport utility it will show which you have.


The way to fix your problem is pretty easy..


Replace the A1143 with the new airport you bought.. set it up correctly to whatever your normal setup is.


Plug in your long cable.. to the new AE.. on the other end plug in the WAN port of the A1143.


Reset it A1143 to factory and redo the setup so it is bridged.


Then plug the computer directly into the LAN ports of A1143 with a short patch cord..


Plug in the TIVO as well and whatever other devices you want.


You can also setup wireless as roaming.


Use the same wireless name and same wireless security setting and password as the main router.


You can now connect by wireless to this AP, and if the old AE is still good it should provide excellent signal in your part of the house that was having issues.


Let me just note.. Cat6 cable come in two types.. solid core for inside the wall.. and stranded for patch cables..


Companies do sell ridiculous length patch cables.. but you are exceeding the length specification..


You are correct that 100M (300 feet aprox) cable is allowed.. but the spec is actually 90M of solid core.. with 10M of stranded cable for patching at each end. Using 30M patch cables was never part of the standard.

Jun 16, 2015 4:53 PM in response to LaPastenague

Thank you for that solution.


To be sure I communicated my layout: My A1143 is on the opposite end of the house 80 to 90 feet from the room the long cable goes to. The location of one of the Macbooks is only about 20 to 30 feet from the A1143 - but through a brick wall. If I move the A1143 to the end of the long cable it will be about 50 or 60 feet from the Macbook. Actually there's a range extender a few feet from the Macbook that I had to use to get a signal around the brick walls. Most other interior walls are Ok (not brick) but there is a massive brick fireplace directly between the Macbook and the room where the A1143 would go.


Since the new Airport Extreme would go where the A1143 is now (opposite end of the house) it would be 20 to 30 feet from the Macbook but we already know it won't work since Apple did not paln for it to support Macbooks this old.


I am not positive the old A1143 relocated 50 to 60 feet away will suppport that Macbook and also worry that when roaming that Macbook might attempt connection with the closer (albeit weaker) new Airport Extreme and of course if it does it will fail.


Do you think those concerns are valid?


As an alternative what if I kept the A1143 on the same end of the house as the new main Airport extreme so it would have the same distances to the Macbook 20 to 30 feet away and used the long cable plugged directly into the new Airport extreme to support the devices like the Macbook that won't currently connect to the A1143 and automatically negotiate a DHCP address.


Maybe I should ask if the Macbook would still have this problem connecting and automatically negotiating the right speed over a long cable if directly connected to a lan port on a new Apple Airport? If so, and the negotiating problem isn't with the A1143, then my last alternative wouldn't work.


Plus it may also not work if the two Airport routers have to be far apart. How far apart? The other device I was using the Macbook to troubleshoot is a ZeeVee QAM modulator which uses its ethernet port for configuration via browser and for software updates so it really doesn't need speed. 10M would be fine but even though the A1143 does support 10M "when forced to" (as you showed me how to do above) it's automatic negotiation fails just like the Macbook's "automatic" negotiation does and I have no way to force it to use 10M.


Do you know the reason why the automatic negotiation fails to discover 10M works? When set on automatic it is "supposed to" try 1000, 100 and then 10M right?


Thanks again for sharing your vast knowledge.

Jun 17, 2015 3:54 AM in response to Nexsen

I am not positive the old A1143 relocated 50 to 60 feet away will suppport that Macbook and also worry that when roaming that Macbook might attempt connection with the closer (albeit weaker) new Airport Extreme and of course if it does it will fail.

The Mac will always connect to the best signal.. so you do not even have to worry..


As an alternative what if I kept the A1143 on the same end of the house as the new main Airport extreme so it would have the same distances to the Macbook 20 to 30 feet away and used the long cable plugged directly into the new Airport extreme to support the devices like the Macbook that won't currently connect to the A1143 and automatically negotiate a DHCP address.

This is the same thing the other way around and is OK.. i did pick the new one to go next to the modem because it is a superior and much faster router.. but if your internet speed is not so fast it won't matter much.


Maybe I should ask if the Macbook would still have this problem connecting and automatically negotiating the right speed over a long cable if directly connected to a lan port on a new Apple Airport? If so, and the negotiating problem isn't with the A1143, then my last alternative wouldn't work.

Trial and error is the learning method here.. I cannot predict the outcome.. try and see.. if it fails buy a new wireless router.. something with ergs.. the poor old airports have never been noted as decent wireless routers for long distance.. so buy high power units.. eg ubiquiti or outdoor wap from TP-Link etc.


Do you know the reason why the automatic negotiation fails to discover 10M works? When set on automatic it is "supposed to" try 1000, 100 and then 10M right?

Yes, but I would like you to test the cable more.. If this is in the wall.. get a cabler with a full test fluke meter to test the actual speed of the wire.. not just continuity tests.


Also note if you wired this yourself.. you must not just get continuity correct .. you MUST NOT BREAK THE PAIRS.


Ethernet is a balanced signalling system based on twisted pair.. break even one pair and it will operate very poorly.. some devices will work and others won't.


Tell me who wired it.. is it solid core in the wall.. if so you should get a cabler back to check it.


If it is long extension.. replace it with solid core.. it must be the correct specification cable to work.. 30M of stranded ethernet will not work.

Jun 17, 2015 12:04 PM in response to LaPastenague

Thanks again.


The long cables were installed by an electrician but I did have to correct a few RJ45 terminations. They are solid core all the way - no terminations or wall plates or patch cords from the A1143 router to the ZeeVee modulator (and Macbook used for testing this).


As for not "splitting the pairs" do you mean making sure the solid color and striped version of that color wires are kept adjacent?


I verified they are wired that way: blue then blue stripe, orange then orange stripe, green then green stripe and brown then brown stripe


That electrician does not have a TDR meter or anything to actually verify cable speed, however so i suppose it is definitely some punch down connections although making contact might have higher resistance causing reflections. But all 4 cables behave the same so if the reason I can't connect is substandard cables that would mean every cable has at least one hgh resiatsnc crimped connection.


But even if that is the case - that the cables will only support 10 M - that doesn't explain why both Macbook and ZeeVee modulator fail to connect at 10M when set to "automatically" negotiate the speed. Since the Macbook "will" connect at 10M when forced to MANUALLY it means the cable at least supports 10M but neither the Macbook nor ZeeVee modulator's AUTOMATIC "negotiation" with the A1143 finds 10M acceptable.


Also, I think I mis-communicated my "alternative" question above: I was talking about placing both the old A1143 and the new Air Port router on the same end of the house and voiced the concern they may interfere with each other if close. That solution was counting on the new router being able to support the long cable and allow automatic negotiation by the ZeeVee modulator. I really wouldn't care if the speed were 10M for the modulator since I'm not doing any large transfers.

Jun 17, 2015 3:56 PM in response to Nexsen

The long cables were installed by an electrician

My experience is that electricians are fine with AC power.. lousy with data..


The standard for ethernet must be followed strictly.. and the chief problem is that it is not in sequence.

Mostly T568B is followed. It doesn't matter which is used as long as it is strictly adhered to.


Please note the centre pair 4-5 was part of the original design for phone connections. And the colours are reversed. just to add to the fun.


Most people mess up by wiring stripe solid stripe solid.. this is wrong for pair 3-6 which straddles the centre phone pair. Break the pairs and it won't work. Or will work at 10mbit in some cases and not others.. gigabit must have all 4 pairs correct.. 10/100 uses 1-2, 3-6. so unfortunately breaking 3-6 is common and affects everything.


Continuity testing which does work fine with broken pairs is not shown on most cheap test gear.. a better unit will actually show crossed pairs. I had to build my own as I did a lot of patching of switches at one stage.


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Jul 10, 2015 11:01 AM in response to Nexsen

LaPastenague,


I wanted to thank you again for taking your time to educate me on proper cable wiring solving my problem.


And to tell you that you solved "another" that would have been just as baffling if not more so.


To recap, I never suspected cable wiring "because" my Tivo Roamio had been working for over a year with these improperly wired cables. After solving my problem we determined the Tivo was capable of connecting at 10 mb "automatically" whereas the Macbook couldn't do it automatically but could connect at 10 Mb when forced to manually.


After rewiring the Macbook connects at 1000Mb!


Being lazy I did not rewire the Tivo cable since it has worked over a year and 10 Mb didn't cause buffering.


Well, all of a sudden the Tivo can't connect at 10 Mb automatically either. It lost internet connectivty yesterday and after rewiring the cable correctly (as you taught me) it now connects fine.


Your patience in solving my previous problem gave me the solution to this one "before it happened".


Thank you again,


NIck

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Macbook won't connect to Internet over long cable?

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