Nginx Reverse Proxy fail2ban shows the offender as coming from the reverse proxy, definitely dont want to ban that ip.

[Jieiku]

Nginx Reverse Proxy fail2ban shows the offender as coming from the reverse proxy, definitely don't want to ban your reverse proxy and cut off ALL traffic to your site.

I have all my headers in place on the reverse proxy:

# example HTTPS
server {
    listen 443 ssl http2;
    server_name www.example.com example.com;

    ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
    root /var/www/example/;
    index index.html;
    location / {
        proxy_set_header Host $http_host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-Host $host:$server_port;
        proxy_set_header X-Forwarded-Server $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto https;
        proxy_pass http://10.18.20.2:44777;
    }
}

The solution that the other fail2ban package uses is working for me. I did originally try yours first.

This one allows you to define the IP of your proxy, and if defined it will use the X-Forwarded-For header:
https://docs.wp-fail2ban.com/en/4.2/defines/constants/WP_FAIL2BAN_PROXIES.html#wp-fail2ban-proxies

I was able to see in your code, that you say I just need to configure wp-config.php, I am wondering which values you think would actually solve this issue and be able to use your plugin behind a reverse proxy.

In my wp-config.php I have added these lines:

$_SERVER['HTTPS'] = 'on';
$_SERVER['HTTP_HOST'] = 'www.example.com';
define('WP_HOME','https://www.example.com');
define('WP_SITEURL','https://www.example.com');
define('WP_FAIL2BAN_PROXIES','10.18.10.1');

section of your code:

/**
 * Returns the remote IP address of the current visitor.
 *
 * We use `REMOTE_ADDR` here directly. If you are behind a proxy, you
 * should ensure that it is properly set, such as in wp-config.php, for
 * your environment.
 *
 * @see https://core.trac.wordpress.org/ticket/9235
 *
 * @since 0.1.0
 *
 * @return string The remote IP address.
 */
private static function get_remote_ip() {
  if ( empty( self::$ip ) ) {
    self::$ip = preg_replace( '/[^0-9a-fA-F:., ]/', '', $_SERVER['REMOTE_ADDR'] );
  }
  return self::$ip;
}

[thebrandonallen]

You will need to add something to your wp-config.php to fix this. I've updated that comment, and added an additional FAQ (https://wordpress.org/plugins/wp-fail2ban-redux/#%0Ahow%20do%20you%20i%20use%20this%20plugin%20if%20my%20site%20is%20behind%20a%20proxy%2C%20like%20cloudflare%3F%0A). The proxy constant in WP Fail2Ban is handy, but, ultimately, it only effects the plugin. I chose not to add that, because the real fix is to fix it for your whole site. If you're behind a reverse proxy, like Cloudflare, and you only fix the issue for WP Fail2Ban Redux, then everything else on your site that uses IP addresses will be wrong.