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shubhankarsoni's avatar
shubhankarsoni
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Jun 21, 2022

Nginx as Reverse Proxy

Hi everyone, We are using Nginx as a reverse proxy which is in front of 2 clustered application and sitting behind a Load Balancer. We are using ip_hash as Load balancing algorithm for session persi...
application delivery
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Nikoolayy1's avatar
Nikoolayy1
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You seem to have a NAT device (router/firewall) or another proxy before the NGINX.

 

If it is another proxy as this is easily solvalble with F5 with and universal persistance using the XFF header (https://community.f5.com/t5/technical-forum/enable-source-ip-persistence-based-on-x-forwarded-ip-info/td-p/98748) but with nginix you may need to see if you can set the real client ip address to be based on XFF and then see if ip_hash will work as it should or try other methods like "hash" or "consistent_hash" based on the value of the XFF header.

 

https://www.loadbalancer.org/blog/nginx-and-x-forwarded-for-header/

http://nginx.org/en/docs/http/ngx_http_upstream_module.html#sticky

https://www.nginx.com/resources/wiki/modules/consistent_hash/

 

 

Other than that try maybe least_connections load balancing with session cookie:

 

https://docs.nginx.com/nginx/admin-guide/load-balancer/http-load-balancer/

 

https://www.nginx.com/products/nginx/load-balancing/#session-persistence

 

The is another persistance if you do not decrypt the SSL traffic that ssl session persistance by SSL session ID F5 supports this and I do not think Nginx does.

 

shubhankarsoni's avatar
shubhankarsoni
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Jun 22, 2022

Hi Nikoolayy1, Thanks for your suggestion!

We are using Nginx Open Source so, we are not able to use "consistent_hash" algorithm, though we tried but got the error like "unknown directive consistent_hash". Also, regarding LB we don't have much idea which is sitting above our Nginx proxy servers. But, the LB is forwarding the Client IP address using X-Forwarded-For header. We tried configuring in the Nginx but still the issue persists. Here is our website config file 

upstream tomcat{
         ip_hash;
         server 192.168.x.y:8080;
         server 192.168.x.y+1:8080;

}

log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                       '$status $body_bytes_sent "$http_referer"'
                       '"$http_user_agent" "$http_x_forwarded_for"'
                         '--"$proxy_add_x_forwarded_for"--';


server {
     listen 192.168.a.b:80;
     server_name example.com www.example.com;
     access_log  /var/log/nginx/access.log  main;

     client_max_body_size 5120M;
     add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
     add_header Referrer-Policy "strict-origin";
     add_header X-XSS-Protection "1; mode=block";
    



     location / {
         proxy_pass http://tomcat;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
         proxy_set_header X-Real-IP $http_x_forwarded_for;

     }

##where 192.168.x.y , 192.168.x.y+1 are the application servers.
##And
##192.168.a.b:80 is the Nginx server running on port 80

The ouptut in access log file we receive is like below

10.*.*.* - - [20/Jun/2022:19:43:17 +0530] "GET /x/x/x/x HTTP/1.1" 302 154 "https://x.x.x.x/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.67 Safari/537.36" "117.x.x.x%2"

10.*.*.* - - [20/Jun/2022:19:43:17 +0530] "GET /x/x/x/x HTTP/1.1" 302 154 "https://x.x.x.x/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/101.0.4951.67 Safari/537.36" "49.x.x.x%2"

## where 10.*.*.* is the LB IP and 117.x.x.x,49.x.x.x are the Client IP addresses.

##The access log format is  
log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                       '$status $body_bytes_sent "$http_referer"'
                       '"$http_user_agent" "$http_x_forwarded_for"'
                         '--"$proxy_add_x_forwarded_for"--';

We require the session persistance/sticky session hence we have chose the ip_hash algorithm.

Kindly advise if we are missing something or is there anything else needs to be added.

Much Thanks!!