Nginx – Configure Nginx, Kibana, Elasticsearch

My setup

Nginx + Kibana – same box different domain, sub-domain (nginx – example.com, kibana – kibana.example.com)

Elasticsearch – 192.168.100.31

I have used the config defined below. Replaced 127.0.0.1 with Elasticsearch ip 192.168.100.31

https://github.com/elasticsearch/kibana/blob/master/sample/nginx.conf

This setup works within local network. But fails when connecting externally with error message on browser "Error Could not contact Elasticsearch at http://192.168.100.31:9200. Please ensure that Elasticsearch is reachable from your system.".

Kibana config.js points to ip and port 9200 –

  elasticsearch: "http://192.168.100.31:9200",

Note: Changing this port to match port defined in nginx config 8433 makes it stop functioning.

nginx config

server {
    listen          8443 ssl;
    server_name     kibana.example.com;

    access_log  /var/logs/nginx/kibana.access.log main;
    error_log   /var/logs/nginx/kibana.error.log;

    auth_basic "Authorized users";
    auth_basic_user_file /file/location/kibana.htpasswd;

    location / {
        root  /usr/local/kibana-3.1.0;
        index  index.html  index.htm;            
    }       

    location ~ ^/_aliases$ {
        proxy_pass http://192.168.100.31:9200;
        proxy_read_timeout 90;
    }
    location ~ ^/.*/_aliases$ {
        proxy_pass http://192.168.100.31:9200;
        proxy_read_timeout 90;
    }
    location ~ ^/_nodes$ {
        proxy_pass http://192.168.100.31:9200;
        proxy_read_timeout 90;
    }
    location ~ ^/.*/_search$ {
        proxy_pass http://192.168.100.31:9200;
        proxy_read_timeout 90;
    }
    location ~ ^/.*/_mapping {
        proxy_pass http://192.168.100.31:9200;
        proxy_read_timeout 90;
    }

    # Password protected end points
    location ~ ^/kibana-int/dashboard/.*$ {
        proxy_pass http://192.168.100.31:9200;
        proxy_read_timeout 90;
        limit_except GET {
          proxy_pass http://192.168.100.31:9200;
          # auth_basic "Restricted";
          # auth_basic_user_file /file/location/kibana.htpasswd;
        }
    }
    location ~ ^/kibana-int/temp.*$ {
        proxy_pass http://192.168.100.31:9200;
        proxy_read_timeout 90;
        limit_except GET {
            proxy_pass http://192.168.100.31:9200;
            # auth_basic "Restricted";
            # auth_basic_user_file /file/location/kibana.htpasswd;
        }
    }
}

Feels there has to be some proxy setting between nginx and elasticsearch to prevent local ip displayed on browser. Can someone show how to get this configured.