Using NGINX as a forward proxy

[Maxim Dounin]

Hello!

On Fri, Nov 18, 2016 at 02:55:13PM -0500, CJ Ess wrote:

> I know its not encouraged but I am trying to use Nginx (specifically
> openresty/1.11.2.1 which is based on Nginx 1.11.2) as a forward proxy.
> 
> I did a quick setup based on all the examples I found in Google and tried
> "GET http://www.google.com/" as an example and found:
> 
> This does work:
> 
>   location / {
>     resolver 127.0.0.1;
>     proxy_pass $scheme://www.google.com$request_uri$is_args$args;
>   }
> 
> This does not:
> 
>   location / {
>     resolver 127.0.0.1;
>     proxy_pass $scheme://$http_host$request_uri$is_args$args;
>   }
> 
> In the latter example it seems that using the $http_host variable is
> causing the problem - there is a hang for a few seconds then a 502 error is
> delivered.
> 
> Is there any unofficial advice?

Unofficial advice is to try looking into error log, it is expected 
to contain details.

In this particular configuration I see at least the following problems:

- $http_host is used, but Host header won't be available in case of 
  forward proxy; $host is to be used instead, it will also contain 
  host from the request line.

- $request_uri already includes request arguments, "$is_args$args" 
  part is not needed.

-- 
Maxim Dounin
http://nginx.org/