Please read this whole message before doing anything.
This procedure is a diagnostic test. It’s unlikely to solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.
The purpose of this exercise is to determine whether the problem is caused by third-party system modifications that load automatically at startup or login. Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards. Boot in safe mode* and log in to the account with the problem. The instructions provided by Apple are as follows:
- Be sure your Mac is shut down.
- Press the power button.
- Immediately after you hear the startup tone, hold the Shift key. The Shift key should be held as soon as possible after the startup tone, but not before the tone.
- Release the Shift key when you see the gray Apple icon and the progress indicator (looks like a spinning gear).
*Note: If FileVault is enabled under Mac OS X 10.7 or later, you can’t boot in safe mode.
Safe mode is much slower to boot and run than normal, and some things won’t work at all, including wireless networking on certain Macs.
The login screen appears even if you usually log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.
Test while in safe mode. Same problem(s)?
After testing, reboot as usual (i.e., not in safe mode) and verify that you still have the problem. Post the results of the test.
Launch the Terminal application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ If you’re running Mac OS X 10.7 or later, open LaunchPad. Click Utilities, then Terminal in the page that opens.
Drag or copy — do not type — the following line into the Terminal window:
curl -I http://www.apple.com
Press return. You should almost instantly get several lines of output below what you entered, the first of which begins with something like this:
If there's no output within ten seconds, consider that a failure. You can then quit Terminal. Post your results.
Change your router channel. Sometimes this is all you will have to do.
Power cycling the router. Read the router's user manual or contact their tech support for instructions.
System Preferences/Internet & Network/Network
Unlock the padlock
Click the Assist Me button
In the popup window click the Diagnostic button.
System Preferences/Network- Unlock padlock. Highlight Airport. Network Name-select your name. Click on the Advanced button. Airport/Preferred Networks-delete all that is not your network.
Place a check mark next to "Remember networks this computer has joined." Click the OK button and lock the padlock. Restart your computer.
http://support.apple.com/kb/TS1920 Mac OS: How to release and renew a DHCP lease
No internet connection (wireless)
Check to see if an extra entry is present in the DNS Tab for your wireless connection (System Preferences/Network/Airport/Advanced/DNS).
Delete all extra entries that you find.
Place a check mark next to "Remember networks this computer has joined."
Other resources to check into:
I have already spent hours on the internet trying to figure out a solution and have tried almost all of these issues. It really doesn't seem to be a router issue, as all the other programs (ie. Mail, software updates) that require a data connection work immediately. I am only having issues with internet.