Losing network or internet connection after sleep/wake

I used the "new location" procedure about 2 months ago and my 2010 Mac Pro (El Capitan) seemed to be happy again until today. Comcast took the network down for some maintenance. First, the Airport Extremes didn't pick up the signal again (had to reset) after Comcast turned things back on.. then, Mac Pro wouldn't recognize wired connection via the port location that I had built and appliued .. Did SMC and PRAM resets, nothing. Built a new location (Network Preferences showed it was connected all the while, but not getting through to browsers) with the connected Ethernet port and things were back to normal again..

I had this machine since 2010 and never had a networking issue until I built an external image of a Mavericks system (iDVD doesn't work correctly on El Capitan).. When I booted back to the main system is when all this network nonsense started to happen.. Still don't understand why.. Doesn't seem to respond to fixing permissions, clean ups, reboots, etc. Just feels like some flag is getting reset with these new locations when they're built..

Just an update to the above. Turns out (for me) is was Norton Internet / Firewall and it's Connection Blocking.. I turned off the connection blocking in Norton (and turned it on with Apple's Firewall) and booting is absolutely fine now. Need to connect with Norton to find out what's up..

I'm using a wired connection to an Airport Extreme (newer model with current firmware) and my iMac running El Capitan was having this issue. I went and set up the location as described, and for months the problem went away. After recently applying a security patch to the OS, the problem has returned.

The "path of least pain" is to leave Terminal running and when the Internet connection isn't working I run

sudo ifconfig en0 down

wait a few seconds and

sudo ifconfig en0 up

That fixes it until my machine sleeps again. Annoying!

It's March 22 2017 and the issue lives on up to and including macOS Sierra 10.12.

In my case an iMac I use as an iTunes home sharing server would drop wifi (802.11n) during sleep. This in turn would play havoc with Apple's Remote app. which I use on an iPad to control music across multiple sound systems in my house. If Remote gets dropped the only recourse is to restart it, but over time the app gets more and more bogged down. The solution to that is the annoyance of creating a new connection in Remote from scratch. On occasion, the drop would confuse Airport Express music nodes, forcing a hard reset and reconfiguration.

Your network service order solution however has solved these issue. Thanks so much for your contribution which is simple to implement but not obvious to a typical Mac user.

Apple, are you paying attention yet?

[SOLVED]

Had the same issue. WiFi not working after wake up for dozens of seconds (up to couple of minutes in some cases), while WiFi icon shows that WiFi is connected. The problem gone after I disabled DoS protection on router. It seems that my router treated MacOS's rapid DHCP (https://cafbit.com/entry/rapid_dhcp_or_how_do) as an attempt of DoS attack.

Man I have to say.. Thank You!

Ive been struggeling with this connection problem since a year now, found that while transmission ( torrents download manager app ) was running the connection was kept all the time because it does not ever stop to exchange packages to the network even if no download processes are active ( same with Skype or other big internet talking apps ) but it wasnt a real solution.

I did what you suggest and now .. my Mac ( and myself ) can both go to sleep with loosing the connection to our minds!

Once again .. thanks!

It worked ! Thank you very much for the solution! I managed at last to back up to time machine. I have a mac pro early 2008 and every time i started a back up the network connection dropped and put me to a self assigned IP.

I spent 2 days to find a solution and finally worked!

Thank you again

Works great...I have been having this same problem since Lion and was wondering what was up with it; upgraded to Mavericks and still had the same issue so I went to the forums for help.

My WIFI would just randomly crash and not be able to connect until I turned it off and back on, I have tried every other solution including resetting the DHCP and resetting the Airport but none of those worked.

I created this account just for saying Thank you for posting this.

can anyone explain this in german? Thanks

My German is nicht sehr gut. Perhaps this image might help explain.

I've had this problem intermittently on my iMac for years now but this is the first time I've ever googled the problem and I feel much better knowing it's so common.

I've decided to chip in to say that I've always been able to regain the ethernet connection after sleep by simply pulling out and reinserting the ethernet cable at the back of the iMac. It's a bit of a pain but a lot quicker than the rebooting some others were mentioning.

The "new location" solution above looks good but as a lone female tech-phobic user I'm always reluctant to mess with anything for fear of making it worse and the "cable out, cable in" solution has served me well for several years now.

The new location solution is great and harmless , you should do it.

I tried to perform this by creating a new location from the drop down, it worked and stayed onnected after sleeping/closing for exactly one day, then reverted back to its searching for the network in vain. The wifi is at the top of the service order selections for all locations, but every time it sleeps it loses the connection and the network name menu goes blank, I have to manually choose it each time and apply. Help!

Thank you, i tryed it. But it works not long. Today the Connection is faild again. Hmm

Have a 2oo9 Macbook Pro and after updating to Mavericks from Snowleopard WLAN stopped working or at least it works badly, i.e., network is not found after boot or is dropped after sleep. Also, my router is not, most of the time, shown in the list of available networks (yet, others are shown).

Called Apple support today. They told me to delete the folder //Library/Preferences/SystemConfiguration. At least now it looks like it solved the problem. Skeptic, though.