启动系统，提示sendmail有如下提示：
Mar 18 01:45:09 OI-n2 sendmail[608]: [ID 702911 mail.alert] unable to qualify my own domain name (OI-n2) -- using short name
Mar 18 01:53:40 OI-n2 sendmail[1551]: [ID 702911 mail.crit] My unqualified host name (OI-n2) unknown; sleeping for retry
这可以算是sendmail自身的一个bug，解决方法，可在/etc/hosts里添加个域名即可，示例如下：
192.168.168.168 oi-host localhost.localdomain
