root@sirius:~# apt-get install screen

Reading package lists... Done

Building dependency tree

Reading state information... Done

Suggested packages:

  iselect screenie byobu

The following NEW packages will be installed:

  screen

0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.

Need to get 654 kB of archives.

After this operation, 964 kB of additional disk space will be used.

WARNING: The following packages cannot be authenticated!

  screen

Install these packages without verification [y/N]? y

Err http://ftp.fr.debian.org/debian/ wheezy/main screen i386 4.1.0~20120320gitdb                                                                                                                     59704-7

  Cannot initiate the connection to ftp.fr.debian.org:80 (2a01:e0c:1:1598::2). -                                                                                                                      connect (101: Network is unreachable) [IP: 2a01:e0c:1:1598::2 80]

Failed to fetch http://ftp.fr.debian.org/debian/pool/main/s/screen/screen_4.1.0~                                                                                                                     20120320gitdb59704-7_i386.deb  Cannot initiate the connection to ftp.fr.debian.o                                                                                                                     rg:80 (2a01:e0c:1:1598::2). - connect (101: Network is unreachable) [IP: 2a01:e0                                                                                                                     c:1:1598::2 80]

E: Unable to fetch some archives, maybe run apt-get update or try with --fix-mis                                                                                                                     sing?

root@sirius:~#