Who gives a hoot if it is all fine for you. What a useless post for people looking for a solutiuon :-\ Bottom line, 10.6.8 is causing an immense problem with networking (wired and airport) for a lot of people.
In my case, wired networking stopped working. At one point it started working and after a reboot I can't getting it working again :-\ (this is on 27" i5 iMac)
I'm connected to a gigabit managed switch and it is seeing the link just fine. I even tried different network switches and cables, no dice. So Apple screwed a pooch royaly with this update. I suspect the issue is with auto-negotiaton. Heck now Network System Prefs don't even let me set the Ethernet values manualy.
And definetly DO NOT listen to the suggestion to delete the port and re-install! your Mac will not give you the oiption to re-install it, so beware of this misleading information!
I sure hope Apple fesses to their screw up and issues a working update.
I'm now downloading the Combo Update and will try applying it to see if that neboulus sugestions works :-\
Information about computers that DO work after the same update IS relevant.
Please don't take out your frustration on people that respond to a cry for help without self-interest.
I have the same problem. Ethernet just keeps saying "cable unplugged". This is what i've tried that HASN'T worked.
- made new user
- reset PRAM
- reset SMC
- changed locations
- deleted and tried to re-add ethernet (it wasn't even listed to be able to add it)
Bugger of a problem. I wonder if Apple are looking at it.
Ahem, it is a rather safe assumption that most people DO NOT have a problem, hence the posts that claim "gee whiz I don't have a problem" are pure noise and tend to upset people who look for solutions. Think about it, the only time such a post would be relevant if Wall Street Journal had a front page headline saying "Apple screws up an update, leaves users without network connectivty" :-)
Anyway, lets forget about that... and move on to the issue...
I had a moment to look at the problem some more and from log entries in /var/log/kernel.log it looks like the reason the network is not seen is because the network card's MAC address has been wiped!
Here are relevant entries:
Jun 25 03:17:11 krpan kernel: AppleBCM5701Ethernet: 0 0 ReadInRom: no 2nd code header found
Jun 25 03:17:11 krpan kernel: AppleBCM5701Ethernet: 0 0 getAdaptorInfo - have default MAC address. Attempting to recover
Jun 25 03:17:11 krpan kernel: AppleBCM5701Ethernet: 0 0 ReadInRom: no 2nd code header found
Jun 25 03:17:11 krpan kernel: AppleBCM5701Ethernet: 0 0 getAdaptorInfo - still have default MAC address. Stopping.
Jun 25 03:17:11 krpan kernel: AppleBCM5701Ethernet: 0 0 start - getAdapterInfo failed, giving up
Each time I reboot I see the same collection of entries...
Looking further back I see that my card's MAC address was altered by OS X (?) on April 16 from its original value, here is the log entry from a reboot on that day:
Apr 16 20:53:38 krpan kernel: BCM5701Enet: Ethernet address 00:10:18:00:00:00
Now here is my speculation... one of previous updates borked something in ethernet card's ROM and when 10.6.8 was applied on top of that it all fell apart. Or else 10.6.8 itself messed up ethernet card's ROM.
I'll try looking more in depth later tonight when I have more time.
Interesting. We have the same problem, on only 1 of 3 nominally identical iMacs (and in addition a bunch of other iMacs/MacBooks that don't have this problem either). And indeed, I see the same messed up IP address (00:10:18:00:00:00). Reinstalling 10.6 from CD and applying the 10.6.7 combo update allows the machine to work (although with the weird MAC address).
But at some point I'll have to update to 10.6.8, so I hope this gets fixed soon.
It appears that some machines revert to this broken MAC address (e.g. https://discussions.apple.com/thread/2641278?start=0&tstart=0) intermittently. It just didn't seem to cause problems in previous OS X versions (<= 10.6.7). I can confirm that for the 1 machine here we're having this problem with, it's intermittent, and rebooting it sometimes fixes the MAC address problem, and when the correct MAC address shows up, wired networking works even under 10.6.8. If/when it happens again I'm planning to try "sudo ifconfig en0 ether ...." to see if it fixes it.
I´m having the very exact same problem here. My ethernet interface misteriously changed it´s MAC address to that rare 00:10:18:00:00:00.
This is my post: https://discussions.apple.com/thread/3145048
And I´ve allready tryied to mannualy restore the MAC addres calling the "sudo ifconfig en0 ether ..." command, but it keeps saying that the interface do not exist. I´m able to see the rare MAC address when I boot from the OS X Installation disk (only this way it´s able to recognize the ethernet interface).
I have managed to get my wired connection working again. Read on for the gory details...
Couple of days ago I found the 2641278 thread you mention, and I also had no trouble with false MAC address until 10.6.8 update. Thankfully, none of my other three Intel Macs on the same LAN had the issue so I did not even notice it until I started looking into the issue after 10.6.8 update.
I do not think that ifconfig terminal command will be of use because en0 is not even available when the issue occurs under 10.6.8 (this is my speculation based on events I'll describe below).
I did finally got things working again on the afflicted iMac (27" i5 w/ built-in Broadcom 5764 network card), and here is how (the events described are spread over multiple days due to my time constraints):
I first removed the Ethernet device under Network preferences (as suggested by David earlier in the thread). But when I tired to re-add the interface it was not available! Btw, that's when I really got ticked off about David's post, but in the end it was what got me digging deeper and allowed me to ultimately solve my problem... for the time being :-) . So at this point I must thank David for his suggestion.
I tried rebooting, removing power... no dice, Network preferences panel still does not have the ethernet interface available for me to add. So I fire up the Terminal.app and that's when I observe that even ifconfing does not list en0 interafce!
Next I start up the System Profiler and there is nothing listed under the Ethernet Cards section! Wow... that's when I start looking through kernel.log for any clues and find the funny things going on with the MAC address along with the errors I posted about earlier in this thread. Further Googling points me to the above mentioned thread but nothing that would point to a solution (at this point I have already tried applying the 10.6.8 combo update without any success).
Since I have Windows XP installed under Boot Camp I start the iMac in Windows XP and wouldn't you know it, network works fine... I check the MAC address, still the fake one (00:10:18:00:00:00). As mentioned in 2641278 thread, this is a Broadcom MAC address. Next I download the Broadcom Management Application for Broadcom NetXtreme Server card and it tells me the same thing, fake MAC is what it sees on the card :-\
At this point I decide to reboot back to OS X, but on a hunch I choose to do it in Safe Mode (http://support.apple.com/kb/HT1455) by holding down a Shift key. Please note that I booted into Safe Mode right after being in Windows XP, I shutdown down the Windows XP (i.e. powered off the iMac) and when I powered it on I was holding down a Shift key.
Booting into Safe Mode took noticeably longer and you see a progress bar displayed on the screen as well (for a while it looked like nothing was going on, so be patient).
Once OS X is loaded I was presented with a login screen (when booting normally I have it automatically log me in, so that was different) and above the user selection window I could see Safe Mode.
Upon login I bring up Network preferences and even without me doing anything it notifies me that it has detected a new Ethernet! I acknowledge the dialog and interface is added. After a few moments the red dot changes to yellow while it is searching for DHCP server, and finally to green once it received the IP info from the DHCP server, awesome! I then change the interface config to my usual manual settings and also check the MAC address... it has a valid MAC address it used to have in the past!
I double check the kernel.log and find that errors I posted about before are gone as well.
I have since rebooted the iMac numerous times as well as completely shut it down and unplugged it from power without any issues. It has now been (only) two days since things got fixed so I hope issue is resolved.
- remove the Ethernet interface from Network preferences panel
- power off the Mac
- boot the Mac into Safe Mode by holding down a Shift key on your keyboard
- go to Network preference panel and let it re-add the Ethernet interface
- (if necessary) re-apply your setting to the Ethernet interface
- enjoy connectivity :-)
I hope this helps other people as well. Also, I don't think me booting the Mac into Windows was relevant to the solution, but it is yet another potential variable.