nginx reverse proxy e.g.

server {
listen 9999;
server_name frontendName;
location / {
proxy_pass http://backendName;
proxy_set_header   Host backendHostName;
proxy_set_header   X-Real-IP  $remote_addr;
proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
}
}