Disable captive network support in OS X
When your Apple device connects to an access point and the configuration looks right (a DNS and an IP address are assigned to the device), it tries to download a file to test network connectivity. Specifically this file is http://www.apple.com/library/test/success.html for everything below Yosemite and http://captive.apple.com/hotspot-detect.html for Yosemite and above.
If the OS can’t download the file, it assumes you’re behind a Captive Portal,
basically a web form that requires you to authenticate to the network in various ways.
You’ve probably seen them in airports or public Wi-fi networks.
This can be very annoying sometimes.
To disable this default behaviour, you can set this preference:
sudo defaults write /Library/Preferences/SystemConfiguration/com.apple.captive.control Active -boolean false
to completely delete it
sudo defaults delete /Library/Preferences/SystemConfiguration/com.apple.captive.control Active
You can still logon by using your browser and if it doesn’t work, you can mannually
launch the app located at
/System/Library/CoreServices/Captive Network Assistant.app