Finding what is causing my site to issue 301 redirects

Question

I have an URL which is 301 redirecting but I cannot find where or how it is happening and wanted some checks to perform if possible?

• I've checked .htaccess - it's not there
• I've checked cPanel in redirects section - it's not there
• In WordPress, I have the redirection plugin active and it's not there either

Is there anywhere else that could be issuing redirects? I'm at a loss to find out where and how the page is redirecting!

Answer 1

Any of the following can cause redirects:

• .htaccess files (cPanel usually edits one of these files)
• Apache configuration files (usually httpd.conf)
• In code (such as a plugin) that sets a Location: header.
• On the content delivery network (CDN), load balancer, or proxy server that sits between your application server and users

To locate the source of redirects, I usually search all the source code using recursive grep on the command line. I usually search for the URL of the redirect.

URLs can be stored in the database as well (some WordPress plugins might do that), so it would be good to look there as well.

If it is malware that hacked your site and caused the redirect, the URL may be obfuscated in the source code to make finding it harder.

When testing redirects, you may also have to clear your browser's cache. If your site previously returned a redirect for a URL your browser is likely to remember that in cache and keep redirecting even after your site is fixed. This is especially true for 301 permanent redirects compared to 302 temporary redirects.

Answer 2

I just had this happen, took me a while to find the setting but if you are using Plesk then check this setting from Plesk Panel.

Navigate to Home > Subscriptions > yourdomain.com > Websites & Domains > yourdomain.com > Hosting Settings. Then check "Preferred domain" dropdown you can choose www. or domain.

Answer 3

If you are using CloudFlare purge cache and switch to development mode.

Some cache plugins can do redirects as well. Better empty the cache directory.

Theme plugins might have some weird issues as well.

Making a backup and deleting plugin directories one by one can help to find bad apples easily. (In case the logs aren't helpful.)

Maybe this saves some hours for someone.

Answer 4

If using WordPress, place this WordPress filter in theme or plugin code to stack dump. This only works if the redirect is triggering through one of the WordPress helper functions like wp_safe_redirect.

add_filter( 'wp_redirect', function($url) { var_export(debug_backtrace()); } );

Answer 5

This issue was caused by a .htaccess file in a parent directory. This parent had iThemes Security plugin which had inserted some code into htaccess to block execution of the file: install.php which was filtering down to all sub-directories.