Trouble With Dropped Ethernet Connection

What kind of Ethernet cable are you using (CAT 5, CAT 5E or CAT 6)? What happens if you try the other Ethernet port on your Mac Pro?

1) You can reset the networking in 10.6.x by going to /YourHardDrive/Library/Preferences/System Configuration/ and moving the files:

a) com.apple.network.identification.plist

b) NetworkInterfaces.plist

c) preferences.plist

To the Trash can (but don't delete them yet. Then IMMEDIATELY reboot to rebuild those settings! Then upon the reboot open System Preferences->Network and at the top of the pane click on the 'Location' drop-down and create a custom Location calling it whatever you want (like Home or Work or whatever). After creating this new Location near the bottom of the Network pane will be the 'Apply' button to save the new custom named Location.

Really consider getting CAT 5E or better yet CAT 6 Ethernet cable!

Hi Eric,

Did you finally found a permanent fix to the problem?

I've been seeking an answer all over the place, but I'll post my comment here. The short story is that I'm bringing my iMac to the "Genius Bar" tomorrow..the long story is what I typed into the additional comments for my Genius Bar reservation:

"Never used this until I upgraded my Fios service last week and the upgrade will only work with an Ethernet connection. 5e cable works on all of my other Macs but not on my iMac "Either the cable for Ethernet is not plugged in or the device at the other end is not responding." I think the plug on the iMac is bad. I've tried resetting PRAM etc. Works for a few seconds if I spray a can of air, especially the freezing element of the spray."

Report from the Genius Bar.

The feeling was that my logic board was the culprit and a replacement would be $700.

Instead they suggested a USB Eternet Adapter $30.

I purchased the later and it works fine.

However I'm wondering if the logic board was at fault from day one? Most of the posts regarding this issue were related to the iMac.

Unfortunately I never needed the Ethernet for the first three years and now the warranty has long expired.

My original now non-functioning Ethernet was

Marvell Yukon Gigabit Adapter 88E8055 Singleport Copper SA:

Name: ethernet

Type: Ethernet Controller

Bus: PCI

Vendor ID: 0x11ab

Device ID: 0x436a

Subsystem Vendor ID: 0x11ab

Subsystem ID: 0x00ba

Revision ID: 0x0013

Link Width: x1

BSD name: en0

Kext name: AppleYukon2.kext

Location: /System/Library/Extensions/IONetworkingFamily.kext/Contents/PlugIns/AppleYukon2 .kext

Version: 3.2.1b1

Unacceptable solution. Apple has a major problem with this and lots of folks have reported it. My new(jan2012) macbook pro has been fine until the last month and now every day i lose internet connection.

and i've tried diff cables, diff router ports, i've tried wifi and it will lose wifi then reconnect. i've also done every kind of reboot reset smc and pram and etc etc etc and it only solved problem for a while..maybe 30 minutes..maybe almost a day. also it does it with any browser...chrome, safari, firefox...and sometimes it loses it after being in sleep mode..but sometimes it comes out of sleep mode fine and i have internet for 30 minutes or a few hours then i lose it. no ryhme or reason. must be a hardware issue with a bad logic board and you know apple wont want to fix those for free. you know i was willing to pay $1200 for an apple product instead of $400 for a windows laptop because of better performance and nicer os/ui but i'm not going to drop $700 for a new logic board...i can go buy a new windows laptop...a nice one..for less than that.

i understand going for the $30 fix but apple should step up and provide a fix.

ah...i'm not under applecare BUT i bought with amex card adn they extend warranty by a year...so i have until like jan20th i think to make a claim....gotta get the macbook into an apple store and get documented and then submit to amex. thanks.