問題1：
E: Package 'openswan' has no installation candidate
解決方法：創建lzu.list文件
# sudo vi /etc/apt/sources.list.d/lzu.list複製且加入以下內容：目的是加入其它源，增加候選目錄
deb http://mirror.lzu.edu.cn/ubuntu/ precise main restricted universe multiverse
deb http://mirror.lzu.edu.cn/ubuntu/ precise-security main restricted universe multiverse
deb http://mirror.lzu.edu.cn/ubuntu/ precise-updates main restricted universe multiverse
deb http://mirror.lzu.edu.cn/ubuntu/ precise-proposed main restricted universe multiverse
deb http://mirror.lzu.edu.cn/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://mirror.lzu.edu.cn/ubuntu/ precise main restricted universe multiverse
deb-src http://mirror.lzu.edu.cn/ubuntu/ precise-security main restricted universe multiverse
deb-src http://mirror.lzu.edu.cn/ubuntu/ precise-updates main restricted universe multiverse
deb-src http://mirror.lzu.edu.cn/ubuntu/ precise-proposed main restricted universe multiverse
deb-src http://mirror.lzu.edu.cn/ubuntu/ precise-backports main restricted universe multiverse生效lzu.list文件
sudo apt-get update重新運行命令繼續安裝，輸入Y後下面命令裝完。
sudo apt-get install openswan xl2tpd ppp問題2：
NETKEY: Testing XFRM related proc values [FAILED]
解決方案：在命令行裏黏貼以下命令
for each in /proc/sys/net/ipv4/conf/*
> do
> echo 0 > $each/accept_redirects
> echo 0 > $each/send_redirects
> done問題解決！
問題3：
Hardware RNG detected, testing if used properly [FAILED]
Hardware RNG is present but 'rngd' or 'clrngd' is not running.
No harware random used!
解決方案：輸入以下代碼
sudo apt-get install rng-tools