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Mountain Lion disconnect from Ethernet in sleep mode

I have a late 2009 iMac running Mountain Lion. I use a program called LogMeIn to remotely access my iPhone from other computers and my iPhone. This app worked in Lion, since it was able to work even if my iMac was in sleep mode. However, in Mountain Lion, my iMac looses connection to both my Ethernet and Wi-Fi when it is in sleep mode, renedering LogMeIn useless. In order to use it, I had to sett sleep to never in the Energy Saver prefrences.


So basically, all networking stops on sleep, on both Ethernet and Wi-Fi. I did not encounter this problem in Lion, but ever since upgrading to Mountain Lion it's been happening. Does anyone have any suggestions to fix this? Is anyone else havin

iPhone 4S, iOS 5.1.1, Verizon, 16 GB, Black

Posted on Jul 30, 2012 4:07 AM

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Posted on Jul 30, 2012 4:18 AM

If you have not, I would go to your "Applications" folder>System Preferences>Energy Saver> and check the box "Wake for Network Access".


Hope this helps 🙂

234 replies

Oct 26, 2012 11:51 AM in response to tehillim

tehillim wrote:


finally, I found the solution,

changing lease time of DHCP server, from 2hours to 1week.

I think this is the problem of compatibily beetween router and osx.

maybe, osx doesn't request again dhcp ip when he wake up,

and routher disconnect osx and loose his IP.

Do you know how to change the DHCP lease time with a Cisco/Linksys router? I don't see any setting for that when I I view the router in Safari.

Oct 27, 2012 7:52 AM in response to tehillim

tehillim wrote:


hi,


sorry, I dont know, however the following will be helpful.


https://www.google.com/search?q=cisco+dhcp+lease+command

Alas, the Cisco commands listed in the search results don't seem to be of any use to me: The only way I know to interact with my Cisco Linksys E3000 router is through the graphical interface when I point my browser to the IP for the router.


Is there some other way? Note that I do not want to replace the firmware with some 3rd party firmware.

Oct 27, 2012 7:56 AM in response to murrayE

In my case I had troubles before with my iMac over WiFi. But now, everything works fine. I didn't change anything to my router or Mac settings. And it doesn't disconnect anymore.


The only thing I remember was to activate "Back to my Mac".


Now, the thing I have to figure out, is how to configure my router and iMac, to access via SSH tunnel... Cause now and then, my router change its IP, so if I want to access it on the go with my iPhone, and if the IP changed, it doesn't work...


Regards,

Nov 16, 2012 8:17 PM in response to Patrick Merel1

Same problem here...

I have an iMac 3,06 2009 and MBpro 13" 2,4 2010 with Mountain Lion. Both losses network connections in sleep mode.

Tried everything suggested here.


I have an external hard drive connected to iMac, with Snow Leopard on iMac i could acess that drive from my MBpro even with iMac in sleep mode. Now, with MOuntain Lion on iMac, it doesn´t work...


I am really thinking of getting back to Snow Leopard again....

Nov 19, 2012 7:13 AM in response to xanoramix

I hope you'll be happy, but I may have found the solution. At least it worked for me during the last couple of days.


When I use Back to my Mac from my Mac or any other VNC software on my iPad or iPhone, sometimes my iMac at home doesn't want to wake up, and it tells me that my iMac isn't available for the moment. As you noticed, after a few hours of sleep, the iMac dissapears from network and you cannot access it whether you're home or away.


Here is the solution: When I know that I'll need to access my iMac for a reason or another, I go to Safari on my other Mac, or any other device (iPad, iPhone, etc) with iCloud enabled. Then I go to any webpage, google.com for instance. Once there, I simply add this page to my reading list. Then I remove it (or keep it if I was surfing on a great blog or whatever).


After 2 to 3 min, I can access my iMac, I think that the fact to add a page to my reading list, wakes up the iMac to sync it and thanks to that, the iMac is reachable. I tried to add notes, reminders, etc but it doesn't work. The reading list thing seems to be the only turnaround until Apple fix this iMac's sleeping issue.


I tried this solution during an entire week while I wasn't home. Each morning I tried to access my iMac but it didn't work. I tried again and again... nothing. And as soon as I added a page to my reading list, the iMac appears like magic.


Let me know if it works for you!

Nov 26, 2012 8:09 AM in response to sflomenb

I started reading this post, b/c I work for a corporation that is connected to Windows servers via ethernet. After updating to Mountain Lion, my computer would lose connection EVERY time it went to sleep. After calling apple several times, with no solution, I think they figured it out the other day.


Go to System preferences, Network Settings, Click on the gear on the lower left hand corner, set service order, change the order to show Ethernet at the top (mine was defaulted at Bluetooth DUN). I would think the same for wifi but not sure, b/c I am not faced with that problem.


I left my computer on during the Thanksgiving holidays, deep sleep, and came back still connected to all servers and no documents affected!!! RELIEF!


So far, so good. I hope this helps.

Nov 26, 2012 8:21 AM in response to yevinmawson44

Thanks, I'll try that. Cause I'm trying to solve this issue for months. Sometimes I think it's OK for 2 or 3 days, then the problem comes back.


3 days ago I noticed that the iMac was reachable over internet even after deep sleep when many apps were lauched on it. For instance, I let Safari, Mail, Calendar, iTunes, iMessages lauched. Maybe one of these apps keep the connexion in order to update the new content.


Anyway, I'll try yours to be sure. But this issue is crazy. My MacBook Pro works well and I can leave it asleep an entire week it's always available and wakes on lan if I need it.

Mountain Lion disconnect from Ethernet in sleep mode

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