Q: iPhones can't connect to the Internet through time capsule

Has it worked in the past and now failed or never worked?

Apple routers can at times autonomously decide to go into bridge mode. If your cable modem is not a router you MUST have the apple router.. TC in your case working in DHCP and NAT mode.

If you have not done it before reset the TC to factory and redo the setup. Here are my recommendations.

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 you want to use for TM using Airport Utility.

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

eg TCgen5 for basestation and TCwifi wireless name.

 

If the wireless is still a problem set wireless names like TC24ghz and set the 5ghz to different name.. eg.TC5ghz.

Finally use fixed channels for 2.4ghz .. try 11, 9, and 6 in that order.

(leave security off for a few minutes and see if that makes a difference).

For iphone and TV having issues in your setup make sure the TC is doing NAT and DHCP.. try using a different DNS like google public, 8.8.8.8 and 8.8.4.4

 

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.

Ignore this point if you don't understand it .. post back if you have drop out issues.

 

 

4. Make sure IPv6 is set correctly in the computer. ie link-local only for ethernet and/or wireless depending on which you use. Auto is not good enough.

Tell us what cable modem you have, make and model please??

The TC does have issues with some popular brands.. any of the SB series single port modems work poorly.

I had a very similar problem after replacing my cable modem that I have been using in bridging mode. I replaced it after my Internet Service Provider recommended me to do so. After the switch, however, my three computers (two imacs and a macbook air) did connect and function properly, but one Apple TV and two iphones did not get any internet access, although they did get a connection to the wifi of the Airport Time Capsule. My ISP customer support could not help me out. But after reading this post I tried resetting the Airport TC and setting up a new wi-fi network, and that seems to have solved the problem: all devices now connect as expected.

My old cable modem was Netgear CG3700EMR and the replacement is a Compal CH7486e.