Nginx KSPT

stream {
    upstream ksptimap {
        server ksptmail.icc.spbstu.ru:993;
    }

    upstream ksptsmtp {
        server ksptmail.icc.spbstu.ru:465;
    }

    include /etc/nginx/tls.conf;
    ssl_session_cache shared:tls:1m;

    server {
        listen     50465 ssl;
        proxy_pass ksptsmtp;
        proxy_ssl  on;

        proxy_ssl_protocols           TLSv1 TLSv1.1 TLSv1.2;
        proxy_ssl_ciphers DEFAULT:@SECLEVEL=1;

        proxy_ssl_verify        off;
        proxy_ssl_session_reuse on;
    }

    server {
        listen     50993 ssl;
        proxy_pass ksptimap;
        proxy_ssl  on;

        proxy_ssl_protocols           TLSv1 TLSv1.1 TLSv1.2;
        proxy_ssl_ciphers DEFAULT:@SECLEVEL=1;

        proxy_ssl_verify        off;
        proxy_ssl_session_reuse on;
    }
}