What does it mean if URLs in a 404 log end with /& or /m& instead of the file extension?

Question

My 404 log shows many URLs ending with /& or /m& instead of the file extension.

They are getting error 404s, but what is that supposed to do? How do the URLs get changed to that?

Answer 1

My 404 log...

You probably mean the error log. In an apache server, errors are recorded in the error_log file.

... shows many URLs ending with /& or /m& instead of the file extension. They are getting Error 404s but what is that supposed to do?

It means that either a guest or a robot is requesting a URL from your website that ends in /& or /m&. Because you do not have a method to handle that request (such as using mod_rewrite module in apache to redirect the request to a valid resource), the server would assume that one would want a file named & or m& and because neither is found on your server, the guest or robot will receive a 404 error page and the guest's browser would receive an HTTP 404 status which means the resource (be it file, folder, or document) is not found.

How do the URLs get changed to that?

If your server changes them, its because a module is loaded (such as mod_rewrite for apache) that takes the original URL and converts it over to the new URL then processes it. To verify this, you may want to check all your configuration files related to your server to see what modules are actually loaded and turn extended logging on in the server itself to see the details. I'd strongly recommend turning the logging back to default after you're done so your server won't be always slow due to extensive logging.