Support » Plugin: WP Super Cache » Serving pages from behind a proxy

  • At the top of the htaccess it says, “If you serve pages from behind a proxy you may want to change ‘RewriteCond %{HTTPS} on’ to something more sensible”

    I am in the process of setting up/configuring a WAF (Web Application Firewall). I assume this is the equivalent to serving pages from behind a proxy. I would like the WAF to serve https. Can you provide an example of “something more sensible” to change “RewriteCond %{HTTPS} on”?


Viewing 8 replies - 1 through 8 (of 8 total)
  • Saša


    It depends on kind of WAF. If it’s apache module (as mod_security for example) then you don’t need to change anything.

    If it’s reverse proxy then you should replace RewriteCond %{HTTPS} on to RewriteCond %{HTTP:X-Forwarded-Proto} https or RewriteCond %{HTTP:X-Forwarded-Port} 443 but it depends on configuration. If VirtualHost is on custom port then you should also set HTTPS in wp-config.php. More details –

    Hi @stodorovic

    Here is the situation:

    The WAF provides free SSL delivery and doesn’t require my server to send via SSL. I understand that isn’t completely secure but my websites don’t have carts nor do they collect any sensitive data.

    I tried setting it up using the CDN feature of Super Cache but this still left a number of things as mixed content. I figured if I could serve the https version of the cache to their server that it would eliminate the mixed content issue.

    If I replace RewriteCond %{HTTPS} on with the WAF IP addresses or domain like this:

    RewriteCond %{REMOTE_HOST} ^(.*)\.examplecdn\.com$ [NC,OR]
    RewriteCond %{REMOTE_ADDR} ^111\.222\.333\.444$ [NC,OR]
    RewriteCond %{REMOTE_ADDR} ^111\.222\.333\.555$ [NC]

    Will my sites generate the https cache and serve it to the WAF/CDN?



    They are server rules (for serving files), but WPSC should create https files and it isn’t possible without changes in wp-config.php because there isn’t place where you can add custom code before loading advanced-cache.php.

    So, you need to add similar “rules” in wp-config.php. Something like this:

    // in known, safe manner
    $trusted_proxies = array( '', '' );
    if ( ! empty( $_SERVER['REMOTE_ADDR'] ) && in_array( $_SERVER['REMOTE_ADDR'], $trusted_proxies ) ) {
        if ( isset( $_SERVER['HTTP_X_FORWARDED_FOR'] ) ) {
            $ip_addr = explode(',',$_SERVER['HTTP_X_FORWARDED_FOR']);
            $_SERVER['REMOTE_ADDR'] = reset( $ip_addr ); 
    	unset( $ip_addr );
        if ($_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https') {
    unset( $trusted_proxies );

    You should add it before comment: /* That’s all, stop editing! Happy blogging. */.

    I didn’t test this code, but it’s concept. Related to rewrite rules, it’s possible to use mod_setenvif module to set environment variable which could be used later (to avoid repeating same rules which isn’t perfect for performance).

    There is an issue on github – related to optimization of rewrite rules. Probably you could use something like this.

    Hi @stodorovic

    I have an unrelated but related question to my situation.

    I have a significant number of blogs on my network and all of them are configured for a CDN. As I am moving to SSL I need to update the CDN on all sites to the SSL version.

    Is there a quick and easy way to update all sites settings to the same CDN? Ideally, with the ability to later update them individually.




    It’s possible only with custom PHP script. You need to upload it into root directory (where is index.php,wp-load.php) and execute it in browser (


    // Load the WordPress library.
    require_once( dirname(__FILE__) . '/wp-load.php' );
    foreach( get_sites( array( 'public' => 1 ) ) as $site ) {
            update_blog_option( $site->blog_id, 'ossdl_off_cdn_url', '' );

    I hope that you have basic PHP knowledge and you can even get option, replace URL and update it.

    Hi @stodorovic

    I do have a solid foundation in php. I’ve completed a few courses and done quite of bit of my own coding and even contributed to a few plugins – including WP Super Cache several years ago to help get it working with WPTouch Pro. However, when you aren’t coding on a regular basis you tend to lose a few steps.

    I tried the code you provided and the script timed out but nothing was changed.

    I was thinking that it might be easier to do it as a mu plugin. Any thoughts on what that might look like? I will give it a try and let you know how I get on with it.




    It’s possible that some plugin was stuck in bootstrap process. You can add following constants before wp-load.php:

    define( 'DOING_AJAX', true );
    define( 'WP_USE_THEMES', false );
    define( 'SHORTINIT', true );

    It stops bootstrap process after multisite init and you can’t use entire WP API (and WPSC isn’t fully loaded), but get_sites and update_blog_option should work.

    Also, if you have shell access then you can run it as shell command. Something like this:

    cd public_html
    php cdn-update.php

    In this case you should set virtual $_SERVER global (before wp-load.php). Also, it’s possible that you need to run php-cli instead of php. Example:

    $_SERVER = array(
      "HTTP_HOST"      => "",
      "SERVER_NAME"    => "",
      "SERVER_PORT"    => 443,
      "REQUEST_URI"    => "/",

    Also, it’s possible to move these scripts outside public_html to protect them. I’m running various cron jobs via php-cli (custom preload, backup,…).

    After adding the constants I got a 500 Server Error. I removed them one at a time. It was the shortinit that was causing the error.

    I think it worked up to site 900 but for some reason none after that. Fortunately I only have upto 932 so I was able to manually complete the rest.


Viewing 8 replies - 1 through 8 (of 8 total)
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