I generated the following using python and works with the re module. The look-ahead assertions ensure that the correct number of dots or colons appear in the address. It does not support IPv4 in IPv6 notation.
pattern = '^(?=\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$)(?:(?:25[0-5]|[12][0-4][0-9]|1[5-9][0-9]|[1-9]?[0-9])\.?){4}$|(?=^(?:[0-9a-f]{0,4}:){2,7}[0-9a-f]{0,4}$)(?![^:]*::.+::[^:]*$)(?:(?=.*::.*)|(?=\w+:\w+:\w+:\w+:\w+:\w+:\w+:\w+))(?:(?:^|:)(?:[0-9a-f]{4}|[1-9a-f][0-9a-f]{0,3})){0,8}(?:::(?:[0-9a-f]{1,4}(?:$|:)){0,6})?$'
result = re.match(pattern, ip)
if result: result.group(0)
