Nginx configuration to create reverse proxy to Zimbra Mail Client and enable ActiveSync based on Z-PUSH.

Zimbra_nginx_upstream_ActiveSync.sh

upstream zimbramailserver {
    server localhost:8443 weight=1 fail_timeout=300s; # Zimbra Mail client HTTPS port
}

server {
        listen 80;
        server_name mail.*;
        return 301 https://$host$request_uri;
}

server {
	server_name mail.*;
        listen 443 ssl;
    	index index.php;

        ssl on;
        ssl_certificate /etc/letsencrypt/archive/mail.example.com/cert1.pem;
        ssl_certificate_key /etc/letsencrypt/archive/mail.example.com/privkey1.pem;

        access_log   /var/log/nginx/mail-access.log;
        error_log    /var/log/nginx/mail-error.log;

	    root /var/www/html/z-push;

    	location /Microsoft-Server-ActiveSync {
	    	rewrite ^(.*)$  /index.php last;
    	}

        location ~ \.(hh|php)$ {
            fastcgi_keep_conn       on;
            fastcgi_pass            127.0.0.1:9001;
            fastcgi_index           index.php;
            fastcgi_buffers         8 16k;
            fastcgi_buffer_size     32k;
            fastcgi_connect_timeout 300;
            fastcgi_send_timeout    300;
            fastcgi_read_timeout    300;
            fastcgi_param           SCRIPT_FILENAME $document_root$fastcgi_script_name;
            include                 fastcgi_params;
        }   

        location / {
            proxy_pass  https://zimbramailserver;
            proxy_next_upstream error timeout invalid_header http_500 http_502 http_503;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_set_header X-Forward-For $proxy_add_x_forwarded_for;
            proxy_set_header X-Forwarded-Proto https;
            proxy_redirect off;
            proxy_read_timeout 5m;
        }
}

Olá!
Eu tenho mais/menos esse cenário...
No servidor web tem o site e o zimbra está em outro servidor, daí preciso fazer um proxy pro zimbra... eu uso o CloudFlare como DNS... O Zimbra envia email mas não recebe, porque ele consulta no IP do servidor-web...