CODE EXAMPLE FOR PHP

ipv6 pregmatch

'/^(((?=(?>.*?(::))(?!.+3)))3?|([dA-F]{1,4}(3|:(?!$)|$)|2))(?4){5}((?4){2}|(25[0-5]|(2[0-4]|1d|[1-9])?d)(.(?7)){3})z/i'