How do I preserve the requested port when using proxy pass? - nginx

Question

In the long run what I'm trying to do is to be able to connect to any domain through any port, for example, mysite.com:8000 and then through Nginx have it get routed to an internal ip through the same port. So for example to 192.168.1.114:8000.
I looked into iptables although I'm planning on having multiple domains so that really doesn't work for me in this case (feel free to correct me if I'm wrong). I made sure that the internal ip and port that I'm trying to access is connectable and running and also that the ports I'm testing with are accessible from outside my network.
Here's my Nginx config that I'm currently using:
server {
set $server "192.168.1.114";
set $port $server_port;
listen 80;
listen 443;
listen 9000;
server_name mysite.com;
location / {
proxy_pass http://$server:$port;
proxy_set_header Host $host:$server_port;
}
}
Currently what happens is that when I send a request it just times out. I've been testing using port 80 and also port 9000. Any ideas on what I might be doing wrong? Thanks!
EDIT:
I changed my config file to look like the following
server {
listen 9000;
server_name _;
location / {
add_header Content-Type text/html;
return 200 'test';
}
I keep getting the same exact error. The firewall is turned off so it just seems like Nginx isn't listening on port 9000. Any ideas on why that might be the case?

Answer 1

The most effective way would be to have three separate server directives, one for each port. That way, the upstream server isn't dynamic, so Nginx knows it can keep long-lived connections open to each one.
If you really don't want to do this, you might be able to get around it by doing something like this:
proxy_pass http://upstream_server.example:$server_port;
$port doesn't exist, but $server_port does, so that should work. (It's not $port because there are two ports for each connection: the server port and the client port, which are $server_port and $remote_port, respectively.)