Ubuntu
update-manager package

  1. Bug #1412943
  2. Comment #1

Comment 1 for bug 1412943

Revision history for this message
Robert Penz (robert-penz-name) wrote : Re: security.ubuntu.com (2001:67c:1562::XXX) not reachable via HE

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/