Q: Internet connection lost after sleep - Ethernet

After a failed wake-up i tried the following (seen in another post):

sudo ifconfig en0 down
sudo ifconfig en0 mtu 1500 up

Temporarily solved the problem to after next sleep.

Pls. add me to list. 'Have a 13" AIR 3 weeks old connected wirelessly to an Airport Extreme (older model). The majority of the times it awakes from sleep mode it is disconnected. Tried everything, re-setting up airport base station, re-setting airport in system preferences, restarting cable modem, discussing with Genius Bar, the usual suspects. No luck. Problem does not occur with 2nd computer on network, an old MB PRO 15". Am using 10.6.5 on both computers. 'Suggests to me that it has something to do with the AIR set-up?

So we can now make an conclusion, the problem is back in 10.6.5 relates to both Ethernet and wireless on machines which is all from 3 to 4 years old to brand new ones. Anyone heard anything from Apple about this?

Add me to the list. This just started happening on my MBP a few weeks ago and I don't know what update or change created the issue.

Safari and Mail think there is no internet connection when the MBP wakes from sleep while file sharing to a Time Capsule and web surfing with Firefox work just fine. Very odd and very frustrating.

I've been pulling the Ethernet cable to get Safari and Mail to work. I'm directly connected to the TC.

A small update on my case: I sold my iMac 20" a couple of weeks ago for a brand new iMac 27".

iMac 20", wired -> most of time no Internet connection after sleep
MacBook Pro 2006, wireless -> used for a couple of weeks while waiting for the new iMac, never had a problem
iMac 27", wired -> no problem so far (10 days)

The only difference between the two iMacs – excluding the hardware - is that the old 20" was born with Tiger and updated to 10.6.5 through time, while the new iMac had Snow Leopard from the start. I also made a complete reset of the MacBook Pro a couple of weeks ago with Snow Leopard.

Nothing will connect to the internet for me. I notice some others stated Firefox would still recognize the modem. My iMac loses it's internet connection after sleeping about 70% of the time. I then have to unplug and replug my ethernet cable anywhere from once to five or six times to get it to reconnect (usually once or twice).
Anyone else figure out whats going on? It's very, very irritating. I've used Macs for about twenty years and I have to say that I've had more problems with this iMac and Snow Leopard than any previous Mac (at least any running OS X).

I had the same issue, and first thought it was about my very specific network configuration to make my MacbookPro7,1 work in a pure windows environment at work.
I tried the

sudo ifconfig en0 down;
sudo ifconfig en0 up

route but finally noticed this

Jan 20 13:11:13 Mobile1 configd[14]: DHCP en0: RELEASE transmit failed

in the logs which suggested that the system had problems obtaining a new address from the DHCP server. So I went ahead and renewed the DHCP lease in the Network Preferences for en0 - and it remedied the problem.

On the iMac that had problems (now sold) I used a configuration with manual IP, so it shouldn't be a DHCP lease problem

Curious enough, on the new iMac I'm currently using DHCP and never had this issue.

Add me to this list. I'm posting this via Firefox (which still sees my Airport connection) but I'll eventually have to restart as Mail, Safari and Chrome don't see my connection. FWIW Terminal also thinks everything is fine, as I can SSH, ping, etc. with no issues.

I'd love a fix for this.

yes indeed ..... I'm running 10.6.6 on a desktop; ethernet cabled to a Westell (Verizon) router/DSL modem. I performed the following experiment: put my Mac to sleep, waited a few minutes, woke it up and discovered that Chrome was "dead" (couldn't raise any webpages), as was Safari ("not connected to the internet" - though Network Diagnostics said all is fine), and Mail. What does work is FireFox (I cleared the cache to make sure that we were actually going "outside") and SSH.

Quitting Chrome, Mail, and Safari and then re-launching gets them "live" again.

I have a PC with wireless connection to the router: I should see if that "gets out" to the internet when Chrome and the others don't.

This is a pretty annoying problem. Has anyone found the "fix"?
K. R. Kaplan

Back again. Still no resolution to problem. iMac won't keep ethernet connection. Very, very irritating. I recently signed up for a cloud backup plan and the backup is taking even longer than it should due to frequently losing the internet connection. The logs for the backup state, "Reason for stopping backup; The backup destination was disconnected." Then it re-scans the files and starts over. Very, very irritating.
Does anyone have any idea if this is a hardware or software problem or how I can "diagnose" the issue? It looks like some are having software problems, since some of their software connects and some doesn't. I do not live anywhere near an Apple store, so taking it in to the "Geniuses" isn't an option. I fear that very soon my ethernet connector will break from constantly plugging and unplugging the cable and changing it out will be very, very irritating since the cable is threaded through some very tight areas with lots of goodies that will possibly be disrupted in the process.

Did I mention this is very, very irritating?

i started getting worried about the Ethernet cable too, especially after my wife partially knocked the connector out for my display. not cool.

set up another Network Location then flip from one to the other and back again using the Apple Menu > Location menu.

this is what i'm doing now to get the internet connection back again. and yes, very, very irritating!

cgoyette,
Thank you for your suggestion! I did try repeatedly switching back and forth between locations, but it didn't restore my ethernet connection. I feel many people having this issue have a software glitch, and I'm coming to the conclusion that my problem must be hardware related, since absolutely nothing helps except replugging my ethernet cable (or, at times, restarting the computer or re-awakening it). Not sure what to do next. Sure appreciate hearing about your experience, though.

Just talked to apple support for 1 hour. All they can say is keep trying different channels or get a better wireless device that had a stronger signal. If it's plugged into the internet they said to reboot a few items and erase the old. But you would have to call and they could help with that over the phone. Not to helpful and they said it's NOT the computer. Then I asked if they ever look at the forum's to see what everyone is saying, "yes but not him and he couldn't tell me what they had to say about the forums."
So Now I will work my way through every channel and if that doesn't work then plug it in the then call and see what they have to say about that. Not to helpful.

{quote:title=lisaeyre wrote:}
Just talked to apple support for 1 hour. All they can say is keep trying different channels or get a better wireless device that had a stronger signal.{quote}

huh. wonder what brand wireless device they recommend over a 1GB Time Capsule (with a MBP plugged in via Ethernet) ?

NOT the computer, that's some comedy right there.