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Inconsistent Dropping of Ethernet Connection on Macbook Pro

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Hey all..

 

I'm not sure if this is a Hardware issue specific to the ethernet port on my Macbook Pro or an OS issue. I've seen posts on the Apple forum under both hardware and OS and haven't seen any solutions. In fact, under the hardware section (for my model) there doesn't seem to be any posts from Apple Support which I find odd as they're usually pretty good at jumping in.

 

I've run across a problem that's been driving me absolutely bonkers. I have a 1st gen 15" Macbook Pro (early 2006) running Leopard (10.5.7).

 

PROBLEM

I've recently noticed that every once in a while the network connection will drop. This seems to be happening at least once a day, but not at any consistent time nor while doing any consistent activity. I can be browsing the web and then notice that pages won't load. I can be in the middle of an online game and notice I'm disconnected from the server. I can be checking email and then will notice that server requests to check mail are timing out.

 

I bring up a Quicksilver script to GET IP and see that my DHCP address has been dropped.

Trying to manually renew the address doesn't appear to work. I have to reboot the computer and it'll come right up.

 

MY SETUP & TROUBLESHOOTING

  • I have a D-LINK router that serves my whole house. DHCP is turned on.
  • I have a Linksys router (acting as a switch) in my office handling the 3 computers & 1 printer within my home office.
  • All computers in my house (mostly consisting of Windows PC's aside from my Macbook Pro) are configured for DHCP and the router assigns them statically based on their MAC address (in short its really a static DHCP configuration).
  • The only other devices that come up on my network are Virtual Machines as I build a number of servers for testing.
  • Anytime that the Macbook Pro drops its connection I can reach over to either of the other two PC's in my office on the same network and they're always still connected so it surely does not appear to be a problem with either the D-LINK router or the Linksys switch within my home office.
  • Since the reboot always corrects the problem, I'm sure it's not an issue with the ethernet cable connecting my MBP to the switch (that's not touched during the reboot).
  • I've checked/repaired permissions through Disk Utility
  • I've rebooted into Single User Mode and ran FSCK and everything comes up clean.

 

Yes a reboot corrects it, but it has been extremely frustrating and annoying that the connection just randomly seems to drop and I'd like to correct it.

 

Any ideas?

 

Thanks,

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Just to humour me, can you try swapping out the ethernet cable?

 

What is showing up in the network preferences for the ethernet port? Self assigned IP?

 

You can also try creating a new network location - this will reset your network preferences, so will rule out a software issue.

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Just to humour me, can you try swapping out the ethernet cable?

 

What is showing up in the network preferences for the ethernet port? Self assigned IP?

 

You can also try creating a new network location - this will reset your network preferences, so will rule out a software issue.

 

When I started losing the connectivity, one of the first things I did was double check the connectivity of the ethernet cable and when it proved to continuouslly be connected well, I did trade it with one of my other computers which had been working fine. End result? The problem continued & the other computer (now using the same cable that the MBP previously had) has consistently worked without dropping its connection.

 

The network settings for the ethernet connection says (at the moment) That the status is "connected".

It's using DHCP and currently is assigned all it's IP properties from the router.

** next time it drops I'll check the status from within there and take a screenshot.

 

I haven't created a new location yet. I currently have 4 preset locations I created that I choose from:

  • Automatic - all network services turned ON
  • LAN - just ethernet and bluetooth on for when on my internal trusted network
  • WiFi - just the airport turned on
  • Airplaine - all network services turned OFF (kind of like the iPhone Airplane mode)

 

I'll add a 2nd LAN with a new configuration and see if it helps.

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Have you tried just assigning your Macbook a static IP address to see if the issue is a DHCP-specific glitch? That might work around the problem.

Make a new location for the static IP, put in an IP address on the same subnet as your other home computers (e.g, first three IP components the same as your DLink DHCP is assigning, E.g. 192.168.0.... ? Then give it a final component well out of the range of the others. (E.g., if your Dlink usually hands out addresses like 192.168.0.102, give it 192.168.0.202 or 192.168.0.5 - remember it has to be between 2 and 254.) I'm sure if you work at multiple locations using DHCP all the time is more convenient, but keeping a "Home" location sounds more convenient than rebooting all the time. (You'll also want to configure in a DNS address or two, based on your ISP.)

 

 

osx_networkpref_10.5_staticip_netgear.jpg

 

If you have to do this to more than one home computer, you'll want to keep track of which IPs you've assigned already.

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Thanks Car1son, but I've done that. Sorry... should've mentioned that in my original troubleshooting list. It didn't make a difference, however when the connection dropped it still showed the assigned IP address in the GET IP script (as opposed to when it's set via DHCP in which case it appears blank).

 

I prefer using DCHP than static addresses especially for my laptops as it makes it easier to just plug in anywhere without having to reconfigure. (yes, I understand that I can easily create a static or dynamic network location too). I assign the addresses by way of the MAC address at the router so the workstations/laptops always get the same address.

 

I have 6 devices (3 workstations throughout the house for the family, 2 laptops - both mine - plus my iPhone) all assigned addresses between 192.168.1.5-50 plus another half dozen Virtual servers that are all assigned address above 192.168.1.200. They're never on full time and all statically assigned (and documented) so there's no overlap. They're all Windows and/or Linux servers that are used for various testing procedures.

 

It only appears to be this Macbook Pro that's having this inconsistent problem.

It didn't drop yesterday at all.

And... I've recently changed the static IP that it's being assigned via the router over the weekend, but that hasn't helped as it dropped again on Sunday.

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OK, static IP doesn't help, so it's the interface that's gone down, not the DHCP lease that's gotten lost. Can you tell if there's any outgoing traffic?

 

As an alternative to a reboot, try Network prefpane, authenticate, select "Built-in Ethernet" on left (by the way, is it green, yellow, or red?), select "Make Service Inactive" from the working/action/gear pull-down menu thingie at the bottom (next to plus and minus. What is that sprocket called?). Apply. Then make same interface active again and Apply again. See if that kicks it back to life.

 

 

Some possibly interesting terminal command when the interface is jammed up:

bash-3.2#  ifconfig en0   
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet6 fe80::21b:63ff:fe97:e363%en0 prefixlen 64 scopeid 0x4 
inet 192.168.1.28 netmask 0xffffff00 broadcast 192.168.1.255
ether 00:1b:63:97:e3:63 
media: autoselect (100baseTX <full-duplex,flow-control>) status: active
supported media: autoselect 10baseT/UTP <half-duplex> 10baseT/UTP <full-duplex> 10baseT/UTP <full-duplex,hw-loopback> 10baseT/UTP <full-duplex,flow-control> 100baseTX <half-duplex> 100baseTX <full-duplex> 100baseTX <full-duplex,hw-loopback> 100baseTX <full-duplex,flow-control> 1000baseT <full-duplex> 1000baseT <full-duplex,hw-loopback> 1000baseT <full-duplex,flow-control> none



bash-3.2#  route -nv get 17.149.160.49
u: inet 17.149.160.49; u: link ; RTM_GET: Report Metrics: len 128, pid: 0, seq 1, errno 0, flags:<UP,GATEWAY,HOST,STATIC>
locks:  inits: 
sockaddrs: <DST,IFP>
17.149.160.49 
  route to: 17.149.160.49
destination: default
      mask: default
   gateway: 192.168.1.1
 interface: en0
     flags: <UP,GATEWAY,DONE,STATIC,PRCLONING>
recvpipe  sendpipe  ssthresh  rtt,msec    rttvar  hopcount      mtu     expire
      0         0         0         0         0         0      1500         0 

locks:  inits: 
sockaddrs: <DST,GATEWAY,NETMASK,IFP,IFA>
default 192.168.1.1 default en0:0.1b.63.97.e3.63 192.168.1.28



bash-3.2#  netstat -I en0 -i -w 5 
           input          (en0)           output
  packets  errs      bytes    packets  errs      bytes colls
       19     0      18634         21     0       1880     0
        0     0          0          1     0         70     0
        0     0          0          0     0          0     0
^C
bash-3.2# 

The first command checks the status of the en0 (ethernet) interface (UP, active). The second checks if there's a configured route for your traffic (to 17.149.160.49, which is apple.com, which is just an address to use without needing to query DNS, which presumably isn't working.) The latter reports packet and byte statistics in and out on the Ethernet every 5 seconds, just to see if it's making any attempt to actually send data.

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Ok, so this happened to me TWICE today.

 

I've noticed the following:

 

If I bring up a terminal window and run: ifconfig en0 I get the following:

 

Last login: Wed Jul 29 11:25:21 on console
daves-macbook-pro-15:~ dave$ ifconfig en0
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
       inet6 fe80::216:cbff:fe8b:e97%en0 prefixlen 64 scopeid 0x4 
       inet 169.254.135.81 netmask 0xffff0000 broadcast 169.254.255.255
       ether 00:16:cb:8b:0e:97 
       media: autoselect (100baseTX <full-duplex,flow-control>) status: active
       supported media: autoselect 10baseT/UTP <half-duplex> 10baseT/UTP <full-duplex> 10baseT/UTP <full-duplex,hw-loopback> 10baseT/UTP <full-duplex,flow-control> 100baseTX <half-duplex> 100baseTX <full-duplex> 100baseTX <full-duplex,hw-loopback> 100baseTX <full-duplex,flow-control> 1000baseT <full-duplex> 1000baseT <full-duplex,hw-loopback> 1000baseT <full-duplex,flow-control> none
daves-macbook-pro-15:~ dave$              

 

Obviously this shows a 169.254.xxx.xxx address which is wrong, hence my lack of connectivity.

 

I bring up the Network Preferences and the IP address reflects the same incorrect IP address as mentioned above.

I select OFF in the Configure dropdown box and hit Apply. All IP settings are cleared.

Then I select USING DHCP from the Configure dropdown and hit apply.

It DOES NOT properly obtain a new IP address from the router (DHCP server), but a reboot does properly configure the settings and it obtains an IP address. Again, this is without changing, re-inserting or even touching the CAT5 connection.

 

 

So... any other ideas out there? Are we talking about a hardware issue? Driver issue? Setting within OSX?

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If it happens with all network locations I'd say it's a hardware issue.

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If it happens with all network locations I'd say it's a hardware issue.

 

I would've thought that a hardware issue is either good or bad. Either it works or it's broke. But that's what I was afraid of.

 

I have an appointment at a Genius Bar tomorrow anyway for a battery issue (Battery won't hold ANY charge). Its past Apple Care, but it did warp a bit and I'm going to see if there's anything they can do. Being out of work I can't afford to buy a new battery and have been having to run solely on the power cable for a bit. (with a cycle count of only 55, this battery shouldn't have died on me).

 

Anyway, while I'm there I'll ask about the ethernet issue too.

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So I took a trip to the nearest Apple Store yesterday for 2 reasons:

 

1. The battery of my 15" Macbook Pro has been dead for a few months now and just driving me up the wall. Not slowly fading, but dead. It would not charge at all. It only had a cycle count of 55 (well below the reported 300 count that people usually see before life degradation). My Applecare ended in the Spring but since I noticed a slight "buckling" of the battery I figured I'd see what they'd say.

 

- The result? Complete replacement of the battery. I barely had to open my mouth. Just gave them a brief synopsis of what was happening and they whipped out a new battery before I could say anything else. That rocked. Saved me approximately 120-something dollars that a new battery would've cost me (which I didn't have the money for at this time).

 

2. I asked them about the network connection dropping.

 

- after going over all the scenarios I listed above, I knew there was no way they'd be able to diagnose it easily so I just asked about any logs or diagnostics I could run myself to pinpoint the problem. The Genius answer? PING. I think he misunderstood me or underestimated my IT knowledge so I went further into the details of the problem. I wasn't questioning whether I had a connection. I've already established that the connection dropped, the IP address reverted to 169.254.xxx.xxx and all other devices on my LAN were connected and functioning properly.

 

The Genius solution there was to re-install the OS to separate the hardware from software. Any driver issue or rogue software will likely be cleared by re-installing OSX. If it continues to be a problem then the issue is likely on the board and an "out of service" fix can run upwards of $300 through them or less w/ another Apple Certified dealer.

 

So.. as soon as I get a chance I'll run through a full backup of my current data and proceed with an Archive & Install of the system and report back.

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What would be quicker is to do a clean install of OS X to a spare external drive. If it still does it from a totally clean install then it must be a hardware problem. I keep a virgin copy of OS X on a FW drive (although USB will work too as it's an intel box) for this purpose.

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What would be quicker is to do a clean install of OS X to a spare external drive. If it still does it from a totally clean install then it must be a hardware problem. I keep a virgin copy of OS X on a FW drive (although USB will work too as it's an intel box) for this purpose.

 

I guess that depends on your definition of quicker. I can't readily reproduce this problem as it happens at random then I may end up having to run from the USB drive all day. And running OSX from the USB drive is s-l-o-w. It's fast enough if you're just running a few quick tasks, but for extended use? It doesn't quite cut it.

 

Besides I haven't re-installed the OS since I first got Leopard over 1 1/2 years ago, so it's somewhat due (I was going to wait until Snow Leopard, but what the heck).

 

Will report back later.

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24 hours after doing an Archive & Install (saving user settings) and it's dropped twice... once yesterday and once today.

 

Since I'm "out of warranty" (AppleCare expired this spring) it will likely run me in the neighborhood of $300 to hae the board replaced. That's not an option at this time so I'll just have to deal with it.

 

The good news from my visit with the Genius bar was that my battery (which had died on me w/ only a cycle count of 55) was replaced w/o any problems. It died, wouldn't hold a charge and had a slight buckle to it (which I pointed out). At least now I'm mobile again and not constantly tethered to a power outlet.

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