# Advanced Configuration

## Disabling IPv6

On some docker hosts IPv6 may not be enabled. In these cases, the following message may be seen in the log:

> Address family not supported by protocol

The easy fix is to add a Docker environment variable to the Nginx Proxy Manager stack:

```yml
    environment:
      DISABLE_IPV6: 'true'
```


## Custom Nginx Configurations

If you are a more advanced user, you might be itching for extra Nginx customizability.

NPM has the ability to include different custom configuration snippets in different places.

You can add your custom configuration snippet files at `/data/nginx/custom` as follow:

 - `/data/nginx/custom/root.conf`: Included at the very end of nginx.conf
 - `/data/nginx/custom/http.conf`: Included at the end of the main http block
 - `/data/nginx/custom/server_proxy.conf`: Included at the end of every proxy server block
 - `/data/nginx/custom/server_redirect.conf`: Included at the end of every redirection server block
 - `/data/nginx/custom/server_stream.conf`: Included at the end of every stream server block
 - `/data/nginx/custom/server_stream_tcp.conf`: Included at the end of every TCP stream server block
 - `/data/nginx/custom/server_stream_udp.conf`: Included at the end of every UDP stream server block

Every file is optional.


## X-FRAME-OPTIONS Header

You can configure the [`X-FRAME-OPTIONS`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/X-Frame-Options) header
value by specifying it as a Docker environment variable. The default if not specified is `deny`.

```yml
  ...
  environment:
    X_FRAME_OPTIONS: "sameorigin"
  ...
```
