PHP4 IPv6 validation

Incase you don’t have the luxury of PHP5’s filter_ functions, this is a handy regexp:

function validate_ipv6($ip) { $hex = ‘[A-Fa-f0-9]’; $h16 = ”{$hex}{1,4}”; $dec_octet = ’(?:25[0-5]|2[0-4]d|1dd|[1-9]d|[0-9])’; $ipv4 = “$dec_octet.$dec_octet.$dec_octet.$dec_octet”; $ls32 = ”(?:$h16:$h16|$ipv4)”; $ipv6 = ”(?:(?:{$IPv4address})|(?:”. ”(?:$h16:){6}$ls32” . ”|::(?:$h16:){5}$ls32” . ”|(?:$h16)?::(?:$h16:){4}$ls32” . ”|(?:(?:$h16:){0,1}$h16)?::(?:$h16:){3}$ls32” . ”|(?:(?:$h16:){0,2}$h16)?::(?:$h16:){2}$ls32” . ”|(?:(?:$h16:){0,3}$h16)?::(?:$h16:){1}$ls32” . ”|(?:(?:$h16:){0,4}$h16)?::$ls32” . ”|(?:(?:$h16:){0,5}$h16)?::$h16” . ”|(?:(?:$h16:){0,6}$h16)?::” . ”)(?:/(?:12[0-8]|1[0-1][0-9]|[1-9][0-9]|[0-9]))?)”;

$regex = ”/^$ipv6$/”; return preg_match($regex, $ip); }