Question: I know that this is a common question, and there are answers for the same, but the reason I ask this question is because I do not know how to approach the solution. Depending on the way I decide to do it, the solution I can pick changes. Anyways,

I have an AWS EC2 instance. My DNS is handled by Route53 and I own example.com. Currently, on my instance, there are two services running:

```
example.com:80 [nginx/php/wordpress]
example.com:8142 [flask]

```

What I want to do is, make `app.example.com` point to `example.com:8142`. How exactly do I go about doing this? I am pretty sure that I will have to point `app.example.com` to the same IP as `example.com`, since it is the same box that will be serving it. And, nginx will be the first one to handle these requests at port 80. Is there a way with which I can make nginx forward all requests to localhost:8142?

Is there a better way that I can solve this problem?

Answer: 
You could add a virtual host for app.example.com that listens on port 80 then proxy pass all requests to flask:

```
server {
    listen 80;
    server_name app.example.com;

    location / {
        proxy_pass http://localhost:8142;
    }   
}

```
This is how you would do it with apache.

```
$cat /etc/apache2/sites-available/app.conf
<VirtualHost *:80>
    ServerName app.example.com
    ProxyPreserveHost On
    <Proxy *>
        Order allow,deny
        Allow from all
    </Proxy>
    ProxyPass / http://localhost:8142/
    ProxyPassReverse / http://localhost:8142/
</VirtualHost>

```