$ sudo networksetup -listallnetworkservices |grep -v asterisk | while read a; do echo -n "$a: " ; sudo networksetup -getinfo "$a" |grep IPv6 ;done
Thunderbolt Ethernet: IPv6: Off
Wi-Fi: IPv6: Off
VPN (L2TP): IPv6: Off
VPN (L2TP) -old: IPv6: Off
Bluetooth DUN: IPv6: Off
Thunderbolt Bridge: IPv6: Off
Notice how it's not a problem with DNS. DNS is giving me back an IPv4 IP.
brad-allison-mbp:~ brad.allison$ dig +short www.google.com
74.125.30.105
74.125.30.99
74.125.30.106
74.125.30.103
74.125.30.147
74.125.30.104
When I try to connect to that name (www.google.com) I get an IPv6 address that fails. Repeatedly. Then suddenly it flips over to an IPv4 address.
brad-allison-mbp:~ brad.allison$ telnet www.google.com 80
Trying 2607:f8b0:4008:804::2004...
Connected to www.google.com.
Escape character is '^]'.
Connection closed by foreign host.
brad-allison-mbp:~ brad.allison$ telnet www.google.com 80
Trying 2607:f8b0:4008:804::2004...
Connected to www.google.com.
Escape character is '^]'.
Connection closed by foreign host.
brad-allison-mbp:~ brad.allison$ telnet www.google.com 80
Trying 2607:f8b0:4008:804::2004...
Connected to www.google.com.
Escape character is '^]'.
Connection closed by foreign host.
brad-allison-mbp:~ brad.allison$ telnet www.google.com 80
Trying 2607:f8b0:4008:804::2004...
Connected to www.google.com.
Escape character is '^]'.
Connection closed by foreign host.
brad-allison-mbp:~ brad.allison$ telnet www.google.com 80
Trying 216.58.219.164...
Connected to www.google.com.
Escape character is '^]'.
^C^C^]
telnet> quit
Connection closed.
