Same issue here with the exception that all my iOS devices are fine it's just my 2011 iMac that shows a connection but is not connected. Had no issues when I was on an AirPort express. Since the new firmware update was released (7.7.2) the issue is happening more often. Prior to the update it might happen once a day or once every other day. It's happened 3 times today. I think I'm going to exchange for an AirPort Extreme and just use my thunderbolt hard drive to back up. I assume as everyones problems seem to be with the time capsule then the above solution should work?? Has anyone experienced this with the new AirPort Extreme?
After reading this thread, I'm wondering if it's the firmware that is causing my problem. I have an Airport Express that is dropping "offline". The indicator light on the AE shows green but the SSID is not being broadcast and all the computers that connect to it wirelessly are knocked off line. I thought at first it was my cable modem and the router just needing a cold boot. I did that and replaced the cable modem with a new one. Problem seems to be less frequent but still there. I was going to go to my local Apple store and buy the new time capsule and while doing some research to see if the new TC fixes the heat problem of the old one ran into this thread. Now I'm not sure if I want to buy a new one in hopes that the problem isn't my AE but rather it's the firmware. Hmmmmm.
I just picked up a new Airport Extreme ac model last weekend and as having the same issue a lot are reporting where the WAN would drop off, but wifi and internal network was ok. I ran some ping tests against my default router on the cable side and found it was happening every 45-55 min, and would last from 1 to 3 minutes. If I had the Airport Utility open and clicked Renew DHCP Lease, it would imeddiately come back. After about 36 hours, I gave up and put my old router back, which worked ok.
After reading about some people's issues with IPv6 on their cable providers network, I tried the new AE again and made sure to set IPv6 to Link local on the internet tab, and it has been rock solid for nearly 24 hours now. So that was definitely my own issue.
This thread pointed me in the right direction though.
Its the Dhcp server, You have to refresh the DHCP server on the devices.
I had the same problem, I bought a new airport extreme 802.11 AC, initially i thought it was just a defective unit, than I went back and exchanged it for a time capsule 802.11 ac and the same thing happened, I kept it for a week before I got so frosturated I had to return it. I can fix the problem, however other people are computer not so computer savy in my house and getting woken up and text all day because there cell phone and computer lost conection wasn't working for me.. If you can return it still, I sugest doing that, I love apple but this product is significantly under par. If you could get your hands on a 5th gen airport extreme they work great also i have a airport express conected together i get full data coverage and typically 300-450mbs on computers and 72-150 mbs on my cells. I will have to wait until they fix it, I would hope they would replace anyones who bought that generation with a new one once it comes out, but you never know.
Oh yeah,, When i looked into it I found that devices would use what ever was connected into the lan port as an internet conection instead of the wan,, the device sends out bad information..
steps to refresh the dns/ dhcp and domain
3 click on the i with a circle around it (on the right hand side of the network you are connected to)
4. if you see in "search domain something that is not your internet provider or device/ router conected to your time capsule like a non-apple router than you have bad enformation getting sent to your device (its most likely something pluged into one of apples lan ports)
5. scroll down until you you see "renew Lease" than click it
1 system preferences
5 if you click on DNS,, youll find in the search domains something that is once again not correct ( this step is just to show you and mac what is the real problem,, you don't need to do it to temp- fix it)
6 click on TCI/IP
7 click on "Renew DHCP lease"
The same basic steps goes for every type of device, the name alternates between "Renew DHCP Lease" and Renew Lease" and even DNS,, depending on the device operating system...
You will have to do this every time, this happens and for me it did it alot.
my ultimate response to fix it is, if you can return it still return it.
if you cannot return it, and you can unplug any device pluged into Lan ports do so
if you cannot unplug device from the lan port,(or if that dosent fix it) than follow the above steps every time this happens