My airport extreme shows a green light, but won't connect to the internet.

Your problem is typical Yosemite network.. just reboot the Time Capsule.. no luck reboot the network.. do a restart in correct order.. modem.. wait 2min.. TC .. wait 2min.. clients.

No luck then do a full reset of the TC and setup in a way that Yosemite can cope with.

Start from a factory reset. No files are lost on the hard disk doing this.

Factory reset universal

Power off the TC.. ie pull the power cord or power off at the wall.. wait 10sec.. hold in the reset button.. be gentle.. power on again still holding in reset.. and keep holding it in for another 10sec. You may need some help as it is hard to both hold in reset and apply power. It will show success by rapidly blinking the front led. Release the reset.. and wait a couple of min for the TC to reset and come back with factory settings. If the front LED doesn’t blink rapidly you missed it and simply try again. The reset is fairly fragile in these.. press it so you feel it just click and no more.. I have seen people bend the lever or even break it. I use a toothpick as tool.

N.B. None of your files on the hard disk of the TC are deleted.. this simply clears out the router settings of the TC.

Setup the TC again.

Then redo the setup from the computer with Yosemite.

1. Use very short names.. NOT APPLE RECOMMENDED names. No spaces and pure alphanumerics.

eg TCgen5 for basestation and TCwifi wireless name.

If the issue is wireless use TC24ghz and TC5ghz with fixed channels as this also seems to help stop the nonsense. But this can be tried in the second round. ie plan on a first and second round of changes to fix this.. hopefully.. I will point out other steps that can be round2.

2. Use all passwords that also comply with 1. but can be a bit longer. ie 8-20 characters mixed case and numbers.. no non-alphanumerics.

3. If the TC is main router you can skip this point. This is only an issue when the TC is bridged.

Ensure the TC always takes the same IP address.. you will need to do this on the main router using dhcp reservation.. or a bit more complex setup using static IP in the TC. But this is important.. having IP drift all over the place when Yosemite cannot remember its own name for 5 min after a reboot makes for poor networking.

4. Check your share name on the computer is not changing.. make sure it also complies with the above.. short no spaces and pure alphanumeric.. but this change will mess up your TM backup.. so be prepared to do a new full backup. Sorry.. keep this one for second round if you want to avoid a new backup.

5. Mount the TC disk in the computer manually.

In Finder, Go, Connect to server from the top menu,

Type in SMB://192.168.0.254 (or whatever the TC ip is which you have now made static. As a router by default it is 10.0.1.1 and I encourage people to stick with that unless you know what you are doing).

You can use name.. SMB://TCgen5.local where you replace TCgen5 with your TC name.. local is the default domain of the TC and doesn't change.

However names are not so easy as IP address.. nor as reliable. At least not in Yosemite they aren't. The domain can also be an issue if you are not plugged or wireless directly to the TC.

6. Make sure IPv6 is set to link-local only in the computer. For example wireless open the network preferences, wireless and advanced / TCP/IP.. and fix the IPv6. to link-local only. Do the same for ethernet if you use it.

There is a lot more jiggery pokery you can try but the above is a good start.. if you find it still unreliable.. don't be surprised.

You might need to do some more work on the computer itself. eg Reset the PRAM.. has helped some people. Clean install of the OS is also helpful if you upgrade installed.

Tell us how you go.

Someone posted a solution.. See this thread.

Macbook can't find Time Capsule anymore

Start from the bottom and work up.. I have a list of good network practice changes but I have avoided Yosemites bug heaven.

Yosemite has serious DNS bug in the networking application.. here is the lets say more arcane method of fixing it by doing a network transplant from mavericks.

http://arstechnica.com/apple/2015/01/why-dns-in-os-x-10-10-is-broken-and-what-yo u-can-do-to-fix-it/

Same thing applies to the Airport Extreme or the Express if used as router.. just replace TC in the instructions with AE.

Typically, in your type of network configuration, the AirPort Extreme would need to be reconfigured as a bridge. This would allow for the apartment's router to provide the necessary services for Internet access.

When you reset your AirPort it is possible that it reconfigured itself as a router. You should just need to reconfigure it as a bridge. You would do this using the AirPort Utility, as follows:

• Run the AirPort Utility.
• Select your AirPort Extreme, and then, select Edit.
• Select the Network tab.
• Change Router Mode to: Off (Bridge Mode)
• Select Update and allow the base station to restart.

Be sure to have the Ethernet cable coming from the wall socket connected to the WAN (circle-of-dots) port on the AirPort Extreme. Temporarily connect your computer to one of the Extreme's LAN ports. Can it access the Internet now? If not, try using a known good Ethernet cable to rule out the cable being bad.

What model running what firmware.. ??

There is a good chance the WAN IP setup is wrong for building supplied internet.

Give us a screenshot from the airport utility showing the wan IP and any errors.

I am having the similar issue on my end. Airport Utility detects internet but Airport Extreme (AE) wont detect the internet connection or dns servers. Configured with Router Mode: Off (Bridge Mode)

Called my ISP and made sure everything checks out fine. Fortunately I got a pretty savy tech so he knew comcast and apple devices. I will be contacting Apple tomorrow since we attempted all we could with my ISP.

Airport Utility 6.3.4 (634.17)

Airport Extreme ME918LL/A Firmware Version 7.7.3

MBP - Yosemite Mid 2012

After working flawlessly for years, my Airport Extreme Base Station had the same problem you described earlier this week: green light on but no internet connection. So I wandered through the MANY posts at this site, trying a number of things without success, and finally found a suggestion that might have worked: renewing the DHCP lease. I did it 2 days ago and the connection has stayed solid (and fast!) since.

(In Mavericks) Open System Preferences and click on Network. Select Ethernet in the left-hand panel and click on Advanced... (lower right). Click on Renew DHCP Lease.

So far, it's worked for me!

I am having the same issue. Here is a snapshot of my Airport Utility on my Macbook Pro:

I was able to resolve this by rebooting NOT RESETTING my modem and at the exact same time do a HARD reset on my airport... when i configured the airport things worked again

I've suffered with this same problem for over a year. I have Time Warner Cable using a cable modem/router which I subsequently added an Apple Airport Extreme router to get a stronger signal in other parts of my house. I have about 12 different wireless devices on my home network. Some have had no issues connecting to my home network but other devices, such as my iMac desktop and my Macbook routinely fail to connect to the Internet despite finding an IP address. Plus, both of our family's iPhones instantly find our home wireless network but can't actually connect to the Internet until 15 minutes or so after we enter our house. Very strange. I've checked every conceivable forum for help/answers/suggestions. Reset & reconfigured my network settings ad nauseum. Re-booted every device. Nothing has worked. UNTIL TODAY. When I learned that ISP's routinely block ports on their cable modems (My DirecTV technician told me this when he arrived to troubleshoot why our DirecTV system wouldn't connect to the Internet). I don't know the reason(s) why an ISP's default mode would be to block certain ports, or why this problem occurs more often when you have several wireless devices running on the same network, but my DirecTV guy was right. I called TimeWarner, explained my situation and requested that they unblock all of the ports on my modem and VOILA! PROBLEM INSTANTLY SOLVED.