安装了apache2，重启apache2的服务的时候，却报错：
siutung@siutung:/etc/apache2# sudo service apache2 restart
* Stopping web server apache2
apache2: Could not reliably determine the server’s fully qualified domain name, using 203.86.2.51 for ServerName
* Stopping web server apache2
apache2: Could not reliably determine the server’s fully qualified domain name, using 203.86.2.51 for ServerName
解决：
进入/etc/apache2目录，修改httpd.conf文件为如下内容（原httpd.conf文件为空）：
ServerName localhost