Package repositories for old Ubuntu releases are dropped from Ubuntu’s upstream package repository and are removed from Ubuntu package mirrors. However, Ubuntu still makes them available here: http://old-releases.ubuntu.com/ubuntu/. Here is an example /etc/apt/sources.list file for Ubuntu Dapper:
#
# /etc/apt/sources.list
# Ubuntu Dapper 6.06
#
#
# main and restricted:
#
# These are the primary package archives.
#
deb http://old-releases.ubuntu.com/ubuntu dapper main restricted
deb-src http://old-releases.ubuntu.com/ubuntu dapper main restricted
deb http://old-releases.ubuntu.com/ubuntu dapper-updates main restricted
deb-src http://old-releases.ubuntu.com/ubuntu dapper-updates main restricted
deb http://old-releases.ubuntu.com/ubuntu dapper-security main restricted
deb-src http://old-releases.ubuntu.com/ubuntu dapper-security main restricted
#
# universe:
#
# Additional software from the larger pool of debian packages. Gobs and
# gobs of useful software lives here, however, software from this
# repository is ENTIRELY UNSUPPORTED by the Ubuntu team.
#
# Note: Some of the software in this repository may not be under a free
# licence. Please satisfy yourself as to your rights to use the
# software.
#
# Note: Software in this repository WILL NOT receive any review or
# updates from the Ubuntu security team.
#
deb http://old-releases.ubuntu.com/ubuntu dapper universe
deb-src http://old-releases.ubuntu.com/ubuntu dapper universe
deb http://old-releases.ubuntu.com/ubuntu dapper-updates universe
deb-src http://old-releases.ubuntu.com/ubuntu dapper-updates universe
deb http://old-releases.ubuntu.com/ubuntu dapper-security universe
deb-src http://old-releases.ubuntu.com/ubuntu dapper-security universe
#
# multiverse:
#
# Additional software that is "not free", which means the licensing
# requirements of this software do not meet the Ubuntu "main" Component
# Licence Policy.
#
# Note: This software is not supported and usually cannot be fixed or
# updated. Use it at your own risk.
deb http://old-releases.ubuntu.com/ubuntu dapper multiverse
deb-src http://old-releases.ubuntu.com/ubuntu dapper multiverse
deb http://old-releases.ubuntu.com/ubuntu dapper-updates multiverse
deb-src http://old-releases.ubuntu.com/ubuntu dapper-updates multiverse
deb http://old-releases.ubuntu.com/ubuntu dapper-security multiverse
deb-src http://old-releases.ubuntu.com/ubuntu dapper-security multiverse
#
# backports:
#
# Software from a newer release of the distribution, or even from the
# development branch of the distribution, but built against this release.
# It may provide newer features, but should be considered untested.
#
# Note: Software in this repository WILL NOT receive any review or
# updates from the Ubuntu security team.
#
#deb http://old-releases.ubuntu.com/ubuntu dapper-backports main restricted
#deb-src http://old-releases.ubuntu.com/ubuntu dapper-backports main restricted
#deb http://old-releases.ubuntu.com/ubuntu dapper-backports universe
#deb-src http://old-releases.ubuntu.com/ubuntu dapper-backports universe
#deb http://old-releases.ubuntu.com/ubuntu dapper-backports multiverse
#deb-src http://old-releases.ubuntu.com/ubuntu dapper-backports multiverse
Here is an example /etc/apt/sources.list file for Ubuntu Hardy:
#
# /etc/apt/sources.list
# Ubuntu Hardy 8.04
#
#
# main and restricted:
#
# These are the primary package archives.
#
deb http://old-releases.ubuntu.com/ubuntu hardy main restricted
deb-src http://old-releases.ubuntu.com/ubuntu hardy main restricted
deb http://old-releases.ubuntu.com/ubuntu hardy-updates main restricted
deb-src http://old-releases.ubuntu.com/ubuntu hardy-updates main restricted
deb http://old-releases.ubuntu.com/ubuntu hardy-security main restricted
deb-src http://old-releases.ubuntu.com/ubuntu hardy-security main restricted
#
# universe:
#
# Additional software from the larger pool of debian packages. Gobs and
# gobs of useful software lives here, however, software from this
# repository is ENTIRELY UNSUPPORTED by the Ubuntu team.
#
# Note: Some of the software in this repository may not be under a free
# licence. Please satisfy yourself as to your rights to use the
# software.
#
# Note: Software in this repository WILL NOT receive any review or
# updates from the Ubuntu security team.
#
deb http://old-releases.ubuntu.com/ubuntu hardy universe
deb-src http://old-releases.ubuntu.com/ubuntu hardy universe
deb http://old-releases.ubuntu.com/ubuntu hardy-updates universe
deb-src http://old-releases.ubuntu.com/ubuntu hardy-updates universe
deb http://old-releases.ubuntu.com/ubuntu hardy-security universe
deb-src http://old-releases.ubuntu.com/ubuntu hardy-security universe
#
# multiverse:
#
# Additional software that is "not free", which means the licensing
# requirements of this software do not meet the Ubuntu "main" Component
# Licence Policy.
#
# Note: This software is not supported and usually cannot be fixed or
# updated. Use it at your own risk.
deb http://old-releases.ubuntu.com/ubuntu hardy multiverse
deb-src http://old-releases.ubuntu.com/ubuntu hardy multiverse
deb http://old-releases.ubuntu.com/ubuntu hardy-updates multiverse
deb-src http://old-releases.ubuntu.com/ubuntu hardy-updates multiverse
deb http://old-releases.ubuntu.com/ubuntu hardy-security multiverse
deb-src http://old-releases.ubuntu.com/ubuntu hardy-security multiverse
#
# backports:
#
# Software from a newer release of the distribution, or even from the
# development branch of the distribution, but built against this release.
# It may provide newer features, but should be considered untested.
#
# Note: Software in this repository WILL NOT receive any review or
# updates from the Ubuntu security team.
#
#deb http://old-releases.ubuntu.com/ubuntu hardy-backports main restricted
#deb-src http://old-releases.ubuntu.com/ubuntu hardy-backports main restricted
#deb http://old-releases.ubuntu.com/ubuntu hardy-backports universe
#deb-src http://old-releases.ubuntu.com/ubuntu hardy-backports universe
#deb http://old-releases.ubuntu.com/ubuntu hardy-backports multiverse
#deb-src http://old-releases.ubuntu.com/ubuntu hardy-backports multiverse