Thanks for the report.
I'm not sure what's the correct way of showing IPv6 addresses when space is limited.

Maybe we simply truncate the too long IP text using CSS text-overflow ellipsis.

Something like this ?
http://i61.tinypic.com/mrpkic.jpg
Maybe move the hr on the second column in the middle... and use also under the provider / plugin row
Or show a partial address and on :hover show the whole
If is ok, i'll provide the patch

from #4772

There seems to be an aggravation, noticed in Piwik v2.8.1:
Visitor log doesn't show visitor's provider if it comes with an IPv6 adress, pls notice attached screenshot (label "unbekannt" ) .
Settings: GeoIP(PECL) is working with Maxmind's 'GeoLite City', visitor's privacy is set as shown in screenshot.

Pls look at #3581 too.

@mygithuber this is probably not the same thing as what is described in the current ticket right? This ticket is about "how to show long IP addresses". You seem to be facing a bug where some IP addresses can't be resolved to a provider.

If this is the case, you should open a separate ticket.