Other people seem to have the same problem .... e.g. this blog post describes how to prefer IPv4 over IPv6 as security.ubuntu.com does not work
http://zach-adams.com/2015/01/apt-get-cant-connect-to-security-ubuntu- fix/ -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1412943 Title: security.ubuntu.com (2001:67c:1562::XXX) not reachable via HE To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/update-manager/+bug/1412943/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs