The server was frequently attacked by an agent containing java/1.6.0. I planned to configure nginx as follows to block requests
location /{
if($http_user_agent ~* "java/1.6.0"){
rewrite ^(.*)$ http://img.mp.itc.cn/upload/20160716/6362d52b6ade45cdb6e354fd9de64d4a_th.jpg redirect;
}
}
When nginx restarts, the following exception occurs:
nginx: [emerg] unknown directive "if($http_user_agent" in /usr/local/nginx/conf/nginx.conf:86
The reason is:
If and ( are missing a space, if there is no space, he will execute if( $http_user_agent as a command, which is obviously wrong.