OS X System wireless connection is not working.
OS X 10.11
Check Wireless Configuration
- Click WiFi icon in upper right of the Desktop. Select Tempest to connect to the Campus network or select UMS-Guest to connect to the guest network.
- As required, authenticate with user's domain credentials.
- Click WiFi icon in upper right of the Desktop. Select Turn Wi-Fi Off.
- Click WiFi icon in upper right of the Desktop. Select Turn Wi-Fi On
- Restart the computer.
Reset WiFi Preferences
- Create a folder on the Desktop named OldWifiPrefs.
- Click WiFi icon in upper right of the Desktop. Select Turn Wi-Fi Off from the drop-down menu.
- Press Command + Shift + G keys for the Go to Folder prompt, then enter /Library/preferences/SystemConfiguration/
- Move the following files to the OldWifiPrefs folder that was created:
- Restart the computer.
After the issue is resolved, the user may delete the OldWifiPrefs folder.
Create a custom WiFi configuration with DNS
If resetting WiFi Preferences doesn't resolve the issue, follow the instruction below.
- Shut down all Applications that use WiFi.
- Click on the Apple icon in the upper left of the Desktop, Select System Preferences... from the drop-down menu.
- Click on the Network icon in the third row.
- Click to highlight/select Wi-Fi from the list in the column on the left.
- From the Location: drop-down at the top, select Edit Locations...
- Click on the + sign and type in a name for the network configuration (i.e. UMS WiFi). Click Done.
- Join the WiFi network by clicking the WiFi icon in the upper right of the Desktop.
- Back in the Network window, click the Advanced... button in the lower right of the window.
- On the TCP/IP tab, click the Renew DHCP Lease button. At the warning prompt, click Apply.
- On the DNS tab, at the bottom of the left column for DNS Servers:, click the + sign. Add the campus DNS servers (i.e. USM (Portland) 220.127.116.11 and 18.104.22.168)
- Click on the Hardware tab.
- From the Configure: drop-down menu, select Manually.
- From the MTU: drop-down menu, select Custom, then enter 1453 in the field below. Click OK.
- Click Apply.
* User may need to repeat these steps to set up Custom save WiFi configurations for other campuses the user travels to and for off campus. Off campus they can use Google DNS 22.214.171.124 and 126.96.36.199 or the DNS for their Internet Service Provider (ISP).
Reference: http://www.igeeksblog.com/how-to-fix-wi-fi-issues-in-mac-os-x-el-capitan/ and http://osxdaily.com/2015/10/16/fix-wi-fi-problems-mac-os-x-el-capitan/