Depending on what you're trying to do one of the "captive" ping urls works eg http://captive.apple.com http://captive.apple.com This is the url that apple devi

Depending on what you're trying to do one of the "captive" ping urls works eg http://captive.apple.com http://captive.apple.com This is the url that apple devices ping to get the login box up for things like hotel wifi. There's a mozilla one also which is http://detectportal.firefox.com/canonical.html http://detectportal.firefox.com/canonical.html [1] , but that returns a redirect which may or may not work for your use case. [1] https://support.mozilla.org/en-US/kb/captive-portal https://support.mozilla.org/en-US/kb/captive-portal