Ubuntu, Nginx, Tomcat 8, Letsencrypt configuration.

My configuration is as follows: Ubuntu, Nginx, Apache Tomcat 8. I only use Tomcat to run a servlet that queries MySQL and returns JSON. My web pages are served through Nginx. Then I installed LetEncrypt to Nginx. I enabled SSL/TLS encryption mode (Full (strict)) in CloudFlare. My Servlet is working fine when I use port 8080, and return the JSON response. To make it secure I changed Tomcat server.xml connector :

 <Connector port="8443" 
        <UpgradeProtocol className="org.apache.coyote.http2.Http2Protocol" />
            <Certificate certificateFile="/etc/letsencrypt/live/<my-domain>/cert.pem"
                     certificateChainFile="/etc/letsencrypt/live/<my-domain>/chain.pem" />

and commented

 <!-- Connector port="8080" 

Restarted tomcat, but I’m still able to invoke the tomcat servlet directly using 8080 port. But, when I call it from Ajax in my web page, I get this error: net::ERR_SSL_PROTOCOL_ERROR

My Question: How to allow my servlet to be called only from my web page.

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May 4, 2023

Hey @walsayer,

From what you’ve written, it seems like you just need to configure your Nginx as a reverse proxy to Tomcat for everything to work. Your Nginx configuration file (usually located at /etc/nginx/sites-available/default or /etc/nginx/conf.d/your_domain.conf) should include the following:

location /servlet_path {
    proxy_pass https://localhost:8443/servlet_path;
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header X-Forwarded-Proto $scheme;
    proxy_ssl_certificate /etc/letsencrypt/live/<my-domain>/cert.pem;
    proxy_ssl_certificate_key /etc/letsencrypt/live/<my-domain>/privkey.pem;
    proxy_ssl_trusted_certificate /etc/letsencrypt/live/<my-domain>/chain.pem;
    proxy_ssl_verify on;
    proxy_ssl_verify_depth 2;
    proxy_ssl_session_reuse on;

Replace /servlet_path with the actual path to your servlet. This configuration will forward requests from Nginx to your Tomcat server over HTTPS, using the same SSL certificates. Note that you’ll need to have the ngx_http_proxy_module and ngx_http_ssl_module modules enabled in Nginx.

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