四層代理比較方便、簡單，nginx.conf如下

#user  nobody;
worker_processes  1;

#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;

#pid        logs/nginx.pid;


events {
    worker_connections  1024;
}


stream {    
    #9501 埠將以4層TCP協議方式轉發至後端app_sever;
    server {
        
 
listen 9501;                          
        proxy_pass app_server;
    }
    upstream app_server{
        server 172.16.0.248:9511;
        #server 172.22.0.45:30028;
    }

    #代理socket
    server {
        listen 9301;
        proxy_pass socket_server;
    } 
    upstream socket_server{ 
        server 
 
172.16.0.248:9311; #釋出socket1服務端
    }
    
    #代理FTP
    server {
        listen 8666;
        proxy_pass ftp_server;
    } 
    
    upstream ftp_server{
        server 172.16.0.248:21; #FTP要設成被動模式，指定埠範圍（大於>1024)，配置防火牆，否則會被防火牆攔截
    }
} 

FTP被動模式配置