Gallery of installed fonts

I want to view the fonts that are installed on my system. Specifically, I want the client-side (fontconfig) fonts, not the old-style X11 bitmap fonts on the server (for which xfontsel does an adequate job). I guess what I’m looking for would be called a font viewer or font gallery. I want to see a bit of sample text for each font, ideally configurable sample text.

Convince apt-get *not* to use IPv6 method

The ISP I work at is setting up an internal IPv6 network in preparation for eventually connecting to the IPv6 internet. As a result, several of the servers in this network now try to connect to security.debian.org via its IPv6 address by default when running apt-get update, and that results in having to wait for a lengthy timeout whenever I’m downloading updates of any sort.