Internet stops working frequently on OS X Lion

Five times in four hours tonight. Internet sharing/Internet connection go down at the same time, and then I have to do a hard restart to fix it (because Lion won't restart any other way). I thought I had it under control for a while, by only turning Internet sharing on when I absolutely had to, but nope. Full-on stupidity tonight.

I am going to put my fist through this iMac screen any minute now, I swear.

It's not your iMac, it's Lion. I went back to Snow Leopard and have not had a single problem with my internet since. For me, there is nothing about Lion that I need enough to put up with the internet issue.

If I turn on Internet Sharing to share a wireless connection to another laptop via Ethernet cable, then disconnect the shared computer, my entire system requires a hard reset. This happens about 30 mins after watching a Veetle movie in Google Chrome. First I lose my Internet connectivity, then one-by-one applications start freezing until I have to hard resent. When I turn off Internet Sharing, everything is normal.

Apple has got some serious issues with Lion. Internet Sharing should not be bringing down the entire system.

Installing the latest update of OS X Lion seems to solve all the wifi related problems.
It worked for my two mbp from september 2011.

I have installed the latest update, and it has done exactly nothing to fix my problem. Nor does turning Internet sharing off once the problem happens solve anything. I used Internet Sharing over WiFi to stream to my Xbox and whatnot, because I don't currently have a router (and can't afford one right now), so I'm stuck using this broken system. All my software is up to date, but whenever this problem happens (sometimes sixteen or seventeen hours after turning on Internet Sharing, sometimes only minutes after) the only way to restore my connection and my system's stability is to do a hard restart.

My problem must be different than the WiFi issues in this thread I believe. I have the all of the lastest updates, and it doesn't fix it.

This happens when I turn on Internet Sharing from WiFi to Ethernet with nothing connected, then run Flash streaming. About 30 mins later my entire system grinds to a halt forcing me to hard reset. It only crashes in a predictable length of time when I watching a streamed movie, but it is possible it happens at variable times when doing normal activity.

Same problems here. Here's a few things I've learned:

1. It's not related to upgrade. After the problem got bad enough last week, I reimaged the hard drive from scratch and manually copied everything back to ensure it was all clean. Problem reappeared today, after visiting a site with a guest network running Aruba Networks wireless (which seems to be where I went when the problems happened the first time).
2. Once the problems start, many apps completely freeze up, including Outlook, Evernote, Adium, and most anything connected online. Have to force-kill them every time.
3. General response time on the machine gets very sluggish, but I'm not seeing any single process standing out as the culprit in Activity Monitor.
4. Chrome and Safari are both completely hosed, even after you kill and restart them. If I try to bring up a site in them, they both hang, but the same site works in Firefox.
5. The problem seems for me to be related to trying to attach to the Aruba wireless network referenced above. Everything was find after my reimage until I went back to that location.
6. The problem is user based. If I create another user and login as him, everything seems fine. HOWEVER, if the problem happens as my user, system-level apps that use the network, such as app store, will not work as any user. This indicates that there's something that gets started as my user, which runs at a system level and affects the entire machine. I'm still working to figure out exactly what that is. I've disabled all login items to see if I can pin down what process might be responsible for starting this chain reaction.
7. Once the problem starts, it doesn't matter if you're on wired or wireless. It will persist until a restart.
8. I am not using Internet sharing, and I don't think it has anything to do with the issue.
9. When the problem occurs, I can still ping, nslookup, and other network-level commands from terminal just fine. Internet never goes down. It seems like it's really an issue of HTTP protocol being filtered/blocked, and only in some apps. My firewall isn't running, and there are no proxies (though this really smacks of a proxy problem.
10. When there's a problem, it's not with lookup, but with connecting, so appears to be protocol specific.

I will share additional observations as I can. I've opened a case with Apple and we'll see what they say about being able to connect via cmd prompt but not via app store or safari, both of what are inbuilt to the OS.

I get the same problem using the ethernet cable on my 2011 iMac (running latest Lion). Sometimes I'll wake my iMac and it'll say no internet connection even though all my other devices connected to my router will have connection. I then have to turn my iMac WiFi on and then off to get the ethernet cable internet started, and then the connection comes through and I can get online again through the cable (WiFi is off at this point). And this is how I have to do it every single time. All my investigation has led me to believe it isn't my router or cable modem.

This has been happening intermittently since I got my 2011 iMac last summer.

Not sure if any of you have noticed that when it happens, it defaults your system back to factory settings... mostly. It saves all of your files (thank god), but then it changes your firewall and privacy settings. Mine even went as far as removing my backup files. This current system is a huge problem for Apple and someone needs to address these issues before we all lose important data that cannot be replaced. Back up back up back up is all I can say.

One minute I open up Safari and the next minute all of my settings are defaulted to no protection and my backup disappears and it tells me I have never made a backup, which is a load of crap.

When that happens to me, my firewall defaults back to OFF. Freaky. I am positive that the computer becomes vulnerable and is open to hackers when the system gets sluggish the way that it does. I think there is more to it than just seeing what we think we see. ALL of my network settings go back to as if I have never even set up a network, even though it says I am still connected. NOT GOOD.

I kept putting off installing Lion, but decided to bite the bullet. I installed it about a week ago and everything went exceedingly well. Well above my expectations. However, a few days ago I started having the same issues you all are having. It seems to be a timing out issue to me. The last few days when I sign off, I will go to the "sleep" mode. After several hours, when I try to get back on I have to restart it again. As long as I am on the computer, I have never had the internet connection disconnect. Only when I put the computer to sleep and get back on in a few hours is when I have the problem.

Hi,

I have a problem with the network and I think it is indeed related with internet sharing.

Some time after sharing my internet (wifi to eth) everything related with the network stop working, all apps using the network get frozen and are difficult to kill, if I try a "force quit" it does not work inmediately, if I open a terminal and use "kill -9" it may not work at all which is pretty weird. Finally it is imposible to shutdown the system (I need to hold the power button) Worth mentioning that other apps (not related with network) keep working perfectly.

I think some people here may be having a different problem, but this one I am describing is indeed related with internet sharing. Lion have plenty of issues with wifi, for instance, my wifi never works when the computer starts, I need to manually "turn wifi off" and then turn it on. (I have installed all updates, PRAM reset, etc...) Honestly I am quite dissapointed. This is a new iMac that came with Lion so it is not easy to install SL, I have never had this kind of problems with my old iMac with Leopard, and then with SL.

I have posted to 2 or 3 different discussion groups on this. I originally thought it was wifi constantly and intermittently losing connection, but after weeks of frustration, I plugged in ethernet cable and yet the pronlem persists. I have tried all methods of deleting passwords in keychain, refreshing DHCP license, resetting network settings, etc., plugging ethernet cable in directly and nothing works. Every few minutes, not just waking from sleep I have to o into network settings, assist me, and go through the process and while doing this it seems to refresh and reconnect. WOW...Cant get any work done, its worse than dial-up 20 years ago on AOL.

APPLE please help with this.

Any suggestions??ANYONE?

HI, have been reading these posts with interest, as I am experiencing very similar problems in Lion with all browsers working for a while and then eventually stalling. In my case, through wi-fi when a page request stalls, I can sometimes wait for more than 3 - 4 mins for it to eventually open a given page - if at all. I am also an upgrader as opposed to a clean installer which seems to tie-in with most of the experiences here.

I have tried deleting .plist as described earlier and the other fixes, clearing cache etc, and YES after the .plist dump I get a lightening browsing experience across Firefox, Safari, and chrome but unfortunately it is short lived !! An hour later I'm back to wading through treacle. I have found that if during a "freeze" I " Turn wifi OFF" and then back on again quickly, ( biringing up the No Internet Connection Dialogue Page) and then refresh the browser, this UNLOCKS the freeze for a while also. But it gets really frustrating, when you have to do that four or five time in a hour, just to stay online.

It really is time that this issue was fully acknowledged by Apple and resolved. I never had this problem with Snow Leopard and have to admit that I am increasingly drawn to browsing the web using WINDOWS 7 (through parallels) - after all IT JUST WORKS !!!!

A loyal MAC user......who is gradually running out of patience.

Figured mine out.. at least for the last 24hours.

Tried all sollution suggestions and the only tactic that seems to have resolved the issue ( wifi says connected but couldnt load pages, switch on and off, which allowed a minute of internet connection working and then slow and unable to use connection at all...) was logging into router and changing channels to unused chanel number ( found what channels were unused or minimally used in system info app / under network, in utilities).. works like a charm now!!! yay!!!!

~Z