The Next Net

If you are connected to this blog using a IPv6 link, you will notice that near the top of the right column of the front page there is a message saying: "Congratulations ! You're using IPv6 ! Your address is XXXXXXX" In case you ask, the PHP code that performs this check is below:

if (substr_count($_SERVER['REMOTE_ADDR'],":") > 0 &&substr_count($_SERVER['REMOTE_ADDR'],".") == 0) {
echo 'Congratulations ! You're using IPv6 ! Your address is'.$_SERVER['REMOTE_ADDR'].'.';
}  else {
echo "You're just using IPv4. Your address is '.$_SERVER['REMOTE_ADDR'].'.';
}

Update: Martin J. Levy suggested the following, more compact code:

function is_connected_ipv6(){
return (substr_count($_SERVER['REMOTE_ADDR'], ":") > 0 && substr_count($_SERVER['REMOTE_ADDR'], ".") == 0);
}
echo is_connected_ipv6() ? "(via IPv6)" : "(via IPv4)";