nginx如何做反向代理

http {
    include                 mime.types;
    default_type            application/octet-stream;
    client_max_body_size    8m;    ################################################################################
    include /usr/local/u-mail/config/nginx/reverse-proxy.conf;    ################################################################################
    #log_format             main  '$remote_addr - $remote_user [$time_local] "$request" '
    #                             '$status $body_bytes_sent "$http_referer" '
    #                             '"$http_user_agent" "$http_x_forwarded_for"';
    #access_log             logs/access.log  main;
    sendfile                on;    #tcp_nopush             on;
    #keepalive_timeout      0;
    keepalive_timeout       65;    #gzip                   on;    upload_progress         proxied 1m;    ###############################################################################    gzip             on;    #client_max_body_size    50m;    client_body_buffer_size 256k;
    client_header_timeout   3m;
    client_body_timeout     3m;
    send_timeout            3m;
    proxy_connect_timeout   300s;
    proxy_read_timeout      300s;
    proxy_buffer_size       64k;
    proxy_buffers  4        32k;
    proxy_busy_buffers_size 64k;
    proxy_temp_file_write_size        64k;
    proxy_ignore_client_abort        on;    
     
    ###############################################################################
    include                 vhost/*.conf;
}