Here's a quick technical fix for a recent Linux issue I ran into.
I started a fresh Xubuntu 14.10 installation yesterday. The installation went perfectly up until the point when I tried to get updates, at which point some steps would just stop. My internet connection was perfectly solid and the main Ubuntu servers were responding as expected. I changed update servers, tried different sets of sources, and tried to see if there were any problems with existing packages but nothing solved the issue. Every update request, whether through the graphical software updater or through apt-get, would just try to access security.ubuntu.com and then stop without any reported error.
I finally found a solution here. I just needed to edit /etc/gai.conf and uncomment a line - specifically, the last line in this block:
# For sites which prefer IPv4 connections change the last line to
#precedence ::ffff:0:0/96 100
So I suppose this is an issue with IPv4 vs. IPv6, or at least some kind of problem dependent upon getaddrinfo(3). Should have stuck with 14.04 I suppose.