After checking that there was no pending bug report, I was on the verge
of filing a bug report against Zend_Validate_Ip (v1.9.6); that it
doesn't validate all valid IPv6 addresses properly.
On a last second whim, I checked the svn version and lo-and-behold it
has been completely rewritten (from scratch by the looks of it) and
passed every test IP that I had been throwing at the old one.
So that's a big thank you and lots of kudos to Dolf aka freak (and the
rest of the team) for the continuing improvements in ZF.
Roll on the next release,
James.