Internet connection lost after sleep - Ethernet

I'm having the same problem on a 27" i5 new iMac running 10.6.2.

I get around it by going to network, turning Ethernet "off" (under the "configure IPv4 dropdown) and then turning it back on. It's annoying, but better than restarting and it works.

I've been working around this by disconnecting the Ethernet cable and reconnecting it.

Faster and easier for me that wading into System Preferences.

Turning 'Configure IPv6' to Off in the advanced preferences seems to be helping. I have no idea what that does/accomplishes but it seems better!

I'm having a similar problem with a 3 week old iMac 21.5". When it wakes from sleep it takes a while (maybe 30-60 seconds) to connect back to the network. My macbook pro on the smae network connects right away. Could the iMac have a bad airport card?

Saying hi from the Netherlands. I also experiencing this problem on my brand new Imac 27inch i5. Tonight someone is coming and having a look if he can solve it, but i am afraid it's hardware.
What I noticed so far is that it mostly occures when my notebook (also 802.11n) is on the network. As long as this device is turned off, no problem, imac always connects and is steady. My other book (802.11g) has no problems.

I have tried with a digiconnect g router and an airport extreme, the round g edition, not 802.11n. I am working wireless.


*Is there nobody who has had a proper answer from the helpdesk?!* I have called many times, but no proper answer. They where not able to check my connection because I didn't work with an airport extreme router at that moment! When it doesn't work out tonight, I will call in tomorrow, because I have the apple router now, and I am very curious what the solution will be! They will surely get my machine back if it's not solved this week, how is it possible that such an expensive machine works so badly?!?

Hi there from Spain,

I'm having the same issue on my MBPro 15 inch, about 1 year old. I'm running off WiFi and the only solution that works for me so far is to reboot.

This didn't happen before upgrading to 10.6.2 and maybe a few other updates. I remember an update which was about the airport card; unfortunately, I can't positively say that the problem began with that one. I can positively say that this didn't happen with Leopard, nor did it happen (or at least not enough to even register) with 10.6.0 and 10.6.1.

What I do know is that repeatedly deactivating and reactivating the AP interface sometimes gets it to work for a bit, but not enough to be useable. In that state, pinging the router, for instance, will return some echoes after 30 seconds! I had never seen anything like that. The router is a relatively new Cisco which works perfectly well for the rest of the devices, so can't be blamed. The interface as seen by ifconfig en1 would sometimes show as inactive, sometimes active but without IP.

A friend with a newer MBPro 15" complains about the same symptoms, on another network, and using cable. Therefore, it would seem that the issue is not tied to a specific network interface. Most odd.

I'd really love to see this solved, I'm pretty sure it's Apple's fault (i.e., not the router, etc). In the meantime, a workaround that doesn't require a reboot (which is a PITA for me) would be great. So far I haven't been able to find one, though. Next I'll try to fiddle with the firewall and as suggested go to preferences and disable/enable several bits.

After further tweaking, turning on or off 'Configure IPv6' in the advanced preferences has no effect. 😟

I'm cautiously optimistic; I haven't lost the network after sleep ever since I turned off IPv6 configuration. Still crossing my fingers.

On the other hand, I'm running 10.5.8 on an iMac manufactured in March. The new machines running Snow Leopard might have bugs, or might be incompatible somehow. I wonder if there's some mystery setting in SL that even the Apple genius bar hasn't scoped out yet.

There are a lot of threads here (and on the iMac forum) about the same or similar problems; wander around and see if one of their suggestions work. I'm sure someone is going to figure this out pretty quick!

I'm having the same problem with my i5, which is connected by ethernet to my Airport Extreme. After a reboot, the connection is fine.

Try disconnecting and re-connecting the ethernet cable.

Much faster than rebooting.

I've noticed this problem as well, I've had it twice now where I've woken the machine up from sleep mode after putting it to sleep the night before only to find out that I have no network connection despite the fact that the network settings under preferences shows I do. I found that a reboot resolves this problem but that's frustrating and annoying.

Has anyone had a response from apple on this and whether its just a software update on a hardware issue?

t does sound like the network controller isn't always waking up from sleep mode or something to that affect.

I've been having this on my new 27" iMac. I think it may be something to do with routing because the ethernet adaptor still seems to know its IP address and still seems to re-acquire its DHCP address if asked to, but I can't ping the router.

Going to the ethernet interface in the Network preferences and choosing 'Make Service Inactive' followed by 'Make Service Active' fixes it, but that's far from ideal.

I've just made two changes which seem to help - haven't tested thoroughly yet or narrowed down which one made the difference, but I was thinking about what would happen during sleep and waking that didn't happen at other times.

First, I went to the Advanced settings of the ethernet interface and under 'Ethernet' I turned off the auto-negotiation: ie. I set it to 'Configure manually' and whatever settings were in force when it was working normally (in my case 1000base T, full-duplex, flow-control and standard MTU - these will depend on your ethernet switch/router).

Secondly, under the Energy Saver preferences, I turned off 'Wake for network access', in case that was putting the ethernet interface into a funny state.

So far, this seems to have fixed it, but I haven't done the big test of the overnight sleep yet...

Dont know if you solved this but I have a suggestion...

I recently purchase and airport express to stream audio and share a printer.. During the installation of the AE i had to connect it directly to my Imac 24"Intel... I have a wireless router that my imac would automatically log on to.. After the installation of the AE it stopped doing this... After a quite a few different tries at playing with the network settings i did the following:
Open system pref>>Network>>Click on your ethernet connection>> on this screen there is a small gear symbol with a down arrow>> click this and Click on Set Service Order>>Make sure Ethernet is first on this list (in my case since I have a wireless connection I clicked Airport)>>>It worked for me hope it works for you.

OK, all - just to let you know that one or other of the two things I tried does seem to have fixed everything nicely for me. No problems since then.

Message was edited by: Quentin Stafford-Fraser

Quentin,

Im glad it worked for you - I tried both things but no luck for me. Still have the same problem - even from some restarts.