On Sun Mar 09 11:46:55 2014, DROLSKY wrote:
Show quoted text> perl -MRegexp::Common -E 'say q{2001:0db8:0000:0000:0000::1428:57ab}
> =~ /^$RE{net}{IPv6}$/'
>
> This passes without the '$' anchor, but that's not very useful ;)
The regexp is intended to fail here.
If you use an address with a contraction, you must contract at least two groups of hexadecimal digits. However, you example address contains seven groups, meaning you're omitted a single group. That's invalid, and hence the pattern fails to match.