老师，我这边配置 TCP协议 基于域名的反向代理失败了，需要老师您帮忙解答！
nginx的版本是 1.24.0

协议的文档说明：
https://nginx.org/en/docs/stream/ngx_stream_ssl_preread_module.html

我陪着的 nginx 配置文件如下：

user  nginx;
worker_processes  1;

pid        /var/run/nginx.pid;
error_log  /var/log/nginx/nginx.error.log warn;

events {
    worker_connections  1024;
}

#stream模块和http模块是并列级别的，所以stream要写在http{}外边
stream {
    # log_format basic '$remote_addr [$time_local] '
    #              '$protocol $status $bytes_sent $bytes_received '
    #              '$session_time';
    # access_log /var/log/nginx/stream-access.log basic buffer=32k;
    # 为了让这个配置文件简单一些，将配置stream放入到/etc/nginx/conf.d，并以.stream做后缀名。
    # 需要为每个端口创建一个.stream做后缀名的配置文件
    include /etc/nginx/conf.d/*.stream;
}

http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;

    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 /dev/null;
    #access_log  /var/log/dnmp/nginx.access.log  main;

    # hide verson string
    server_tokens  off;
    sendfile        on;
    #tcp_nopush     on;
    client_max_body_size 100M;

    keepalive_timeout  65;

    #gzip  on;

    include /etc/nginx/conf.d/*.conf;
}

	map $ssl_preread_server_name $name {
	    mysql.wvzc.com      	 backend;
	    default                  backend2;
	}

	upstream backend {
	    server host.docker.internal:3305;
	}

	upstream backend2 {
	    server 192.168.0.3:12345;
	    server 192.168.0.4:12345;
	}

	server {
		listen      12346;
		proxy_pass  $name;
		ssl_preread on;
	}

    # 这样配置是对的
    server {
        listen 12345;  # 代理服务器监听的端口
        proxy_pass  host.docker.internal:3305;  # 后端服务器的地址和端口
    }

    # 这样配置是对的
    upstream  mysql.wvzc.com.server {
        server host.docker.internal:3305;
    }

    server {
        listen 188;  # 代理服务器监听的端口
        proxy_pass  mysql.wvzc.com.server;  # 后端服务器的地址和端口
    }

直接访问 nginx 的 12345 和 188 端口可以正常连接 mysql 客户端；

但是通过域名( mysql.wvzc.com )访问 nginx 的 12346 端口，无法与 mysql 建立连接！

不知道问题具体出在哪了。。。。

nginx 的编译配置如下：

sh-4.2# nginx  -V
nginx version: nginx/1.24.0
built by gcc 4.8.5 20150623 (Red Hat 4.8.5-44) (GCC) 
built with OpenSSL 1.0.2k-fips  26 Jan 2017
TLS SNI support enabled
configure arguments: --prefix=/usr/local/nginx --sbin-path=/usr/sbin/nginx --modules-path=/usr/lib/nginx/modules --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --pid-path=/var/run/nginx.pid --lock-path=/var/run/nginx.lock --http-client-body-temp-path=/var/cache/nginx/client_temp --http-proxy-temp-path=/var/cache/nginx/proxy_temp --http-fastcgi-temp-path=/var/cache/nginx/fastcgi_temp --http-uwsgi-temp-path=/var/cache/nginx/uwsgi_temp --http-scgi-temp-path=/var/cache/nginx/scgi_temp --with-perl_modules_path=/usr/lib/perl5/vendor_perl --user=nginx --group=nginx --with-compat --with-file-aio --with-threads --with-http_addition_module --with-http_auth_request_module --with-http_dav_module --with-http_flv_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_mp4_module --with-http_random_index_module --with-http_realip_module --with-http_secure_link_module --with-http_slice_module --with-http_ssl_module --with-http_stub_status_module --with-http_sub_module --with-http_v2_module --with-mail --with-mail_ssl_module --with-stream --with-stream_realip_module --with-stream_ssl_module --with-stream_ssl_preread_module --with-cc-opt='-Os -fomit-frame-pointer -g' --with-ld-opt=-Wl,--as-needed,-O1,--sort-common
sh-4.2#