SOHU 企业邮箱目前所使用的 POP/IMAP 反向代理，以及 SMTP 客户端连接代理配置

mail {
    auth_http 127.0.0.1:9999/auth;

    server {
        pop3_capabilities "TOP" "USER" "UIDL";
        listen 110;
        protocol pop3;
        proxy on;
    }

    server {
        listen 995;
        protocol pop3;
        proxy on;
        ssl                  on;
        ssl_certificate      mail.sohu.net.crt;
        ssl_certificate_key  mail.sohu.net.key;
    }

    server {
        xclient on;
        server_name sohu.net;
        listen 25;
        protocol smtp;
        proxy on;
    }

    server {
        listen 465;
        protocol smtp;
        proxy on; 
        ssl                  on;
        ssl_certificate      mail.sohu.net.crt;
        ssl_certificate_key  mail.sohu.net.key;
    }

    server {
        imap_capabilities "IMAP4" "IMAP4rev1" "UIDPLUS" "AUTH=LOGIN" ;
        imap_client_buffer 8K;
        listen 143;
        protocol imap;
        proxy on;
    }

    server {
        listen 993;
        protocol imap;
        proxy on; 
        ssl                  on;
        ssl_certificate      mail.sohu.net.crt;
        ssl_certificate_key  mail.sohu.net.key;
    }
}