さくらVPS参考
ipv6 http://www.mk-mode.com/octopress/2012/01/22/22002025/ http://rislim.jp/it/133 http://smilemark.net/blog/archives/2011/08/disable-ipv6-centos6.php http://www.takeash.net/wiki/?Linux%2FInstall%2FCentOS6#DisableIPv6
iptables http://fnya.cocolog-nifty.com/blog/2013/02/vps-iptables-0c.html
ssh http://morizyun.github.io/blog/sakura-vps-centos63-ssh-setup/
Node.js http://www.mztm.jp/2013/05/27/sakuranodejs/
LXC http://orangain.hatenablog.com/entry/multi-node-serves-using-lxc-on-sakura-vps