Objectivo

Se um dos objectivos do Debian é a estabilidade, o seu preço é a utilização de software bastante testado e, portanto, antigo. No entanto, pode surgir necessidade de instalar software mais recente o inexistente à data de saída do debian etch. Para isso existe o repositório backports, que disponibiliza versões mais recentes ou inexistente à data de lançamento do etch.

Configuração

A localização do repositório deve ser adicionada à lista existente em /etc/apt/sources.list:

#
# deb cdrom:[Debian GNU/Linux 4.0 r0 _Etch_ - Official i386 NETINST Binary-1 20070407-11:29]/ etch contrib main

deb http://ftp.pt.debian.org/debian/ etch main contrib
#deb-src http://ftp.pt.debian.org/debian/ etch main

deb http://security.debian.org/ etch/updates main contrib
#deb-src http://security.debian.org/ etch/updates main contrib

# debian-volatile
deb http://volatile.debian.org/debian-volatile etch/volatile main contrib non-free

# debian-backports
deb http://www.backports.org/debian etch-backports main contrib non-free

A chave pública do repositório backports também deve ser adicionada à lista de chaves conhecidas pelo apt:

server:~# apt-get install debian-backports-keyring
Reading package lists... Done
Building dependency tree... Done
The following NEW packages will be installed:
  debian-backports-keyring
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 3310B of archives.
After unpacking 49.2kB of additional disk space will be used.
WARNING: The following packages cannot be authenticated!
  debian-backports-keyring
Install these packages without verification [y/N]? y
Get:1 http://www.backports.org etch-backports/main debian-backports-keyring 2007.06.10 [3310B]
Fetched 3310B in 0s (15.1kB/s)
Selecting previously deselected package debian-backports-keyring.
(Reading database ... 30570 files and directories currently installed.)
Unpacking debian-backports-keyring (from .../debian-backports-keyring_2007.06.10_all.deb) ...
Setting up debian-backports-keyring (2007.06.10) ...
OK

Verificação

É possível listar as chaves utilizadas pelo apt:

server:~# apt-key list
/etc/apt/trusted.gpg
--------------------
pub   1024D/2D230C5F 2006-01-03 [expired: 2007-02-07]
uid                  Debian Archive Automatic Signing Key (2006) <ftpmaster@debian.org>

pub   1024D/6070D3A1 2006-11-20 [expires: 2009-07-01]
uid                  Debian Archive Automatic Signing Key (4.0/etch) <ftpmaster@debian.org>

pub   1024D/ADB11277 2006-09-17
uid                  Etch Stable Release Key <debian-release@lists.debian.org>

pub   1024D/BBE55AB3 2007-03-31 [expires: 2010-03-30]
uid                  Debian-Volatile Archive Automatic Signing Key (4.0/etch)
sub   2048g/36CA98F3 2007-03-31 [expires: 2010-03-30]

pub   1024D/16BA136C 2005-08-21
uid                  Backports.org Archive Key <ftp-master@backports.org>
sub   2048g/5B82CECE 2005-08-21