想建立一个测试用的虚拟主机，遇到了这个问题：
[[email protected] html]# service httpd start
Starting httpd: httpd: Could not reliably determine the server's fully qualified domain name, using localhost.termwikidev for ServerName
(13)Permission denied: make_sock: could not bind to address [::]:81
(13)Permission denied: make_sock: could not bind to address 0.0.0.0:81
no listening sockets available, shutting down
Unable to open logs
解决办法：
semanage port -l|grep http
semanage port -a -t http_port_t -p tcp 81
这个两个命令一是查看，一个是添加，添加完再查看一遍，如果有81，则成功。另可能要以root用户运行。
如果semanage命令不存在
bash: semanage: command not found
安装 policycoreutils-python-2.0.83-19.39.el6.x86_64.rpm
涉及到的包有