network captive detect URL
curl --resolv play.googleapis.com:80:127.0.0.1 http://play.googleapis.com/generate_204 curl --resolv www.msftconnecttest.com:80:127.0.0.1 http://www.msftconnecttest.com/connecttest.txt curl --resolv ipv6.msftconnecttest.com:80:127.0.0.1 http://ipv6.msftconnecttest.com/connecttest.txt wget -4 https://connectivitycheck.gstatic.com/generate_204 wget -4 https://www.google.com/gen_204 wget -4 http://connectivitycheck.gstatic.com/generate_204 wget -4 http://www.google.com/gen_204 wget -6 https://connectivitycheck.gstatic.com/generate_204 wget -6 https://www.google.com/gen_204 wget -6 http://connectivitycheck.gstatic.com/generate_204 wget -6 http://www.google.com/gen_204 wget http://ipv6.google.com/gen_204 wget https://ipv6.google.com/gen_204