Ubuntu官方专门出了一个 old-release的镜像

deb http://old-releases.ubuntu.com/ubuntu/ karmic main restricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ karmic-security main restricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ karmic-updates main restricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ karmic-proposed main restricted universe multiverse
deb http://old-releases.ubuntu.com/ubuntu/ karmic-backports main restricted universe multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ karmic main restricted universe multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ karmic-security main restricted universe multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ karmic-updates main restricted universe multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ karmic-proposed main restricted universe multiverse
deb-src http://old-releases.ubuntu.com/ubuntu/ karmic-backports main restricted universe multiverse

其他Ubuntu Linux版本的只需要讲karmic改成其版本代号即可。这样过期后的版本也可以继续使用了。

其中各版本代号为：

4.10 - Warty Wartho 多疣的疣猪
5.04 - Hoary Hedgeh 白发的刺猬
5.10 - peezy Badger 活泼的獾
6.06 - Dapper Drake 整洁的公鸭
6.10 - Edgy Eft 尖利的小蜥蜴
7.04 - Feisty Fawn 烦躁不安的小鹿
7.10 - Gutsy Gibbon 胆大的长臂猿
8.04 - Hardy Heron 坚强的苍鹭
8.10 - Intrepid Ibex 无畏的高地山羊
9.04 - Jaunty Jackalope 活泼的兔子
9.10 - Karmic Koala 幸运的无尾熊
10.04 - Lucid Lynx 清醒的猞猁
10.10 - Maverick Meerkat 标新立异的的狐獴
11.04 - Natty Narwhal 敏捷的独角鲸
11.10 - Oneiric Ocelot 有梦的虎猫
12.04 - Precise Pangolin 精准的穿山甲
13.04 Raring Ringtail急切的浣熊
14.04 LTSTrusty Tahr 俏皮的蝾螈
14.10 Utopic Unicorn 乌托邦独角兽
15.04 Vivid Vervet 长尾黑颚猴