What is 404 error means?
404 Error is an error web page when you visited any URL which doesn’t exist.
For example, your website has only 4 pages like following:
But you don’t have any contact page like “yourwebsite.com/contactus” yet.
When you open your browser and try to go “yourwebsite.com/contactus” your server generate an error page called 404 error page. This means the url you try to visit doesn’t exist for a reason. This typically means that you entered a wrong address or page never exist or be deleted.
This is what 404 error means.
Why does 404 error matter to my website security?
Here is why.
When hackers try to break in your website, they try to visit commonly used URLs for administrator access page like..
So these invaders try to visit these pages see if they can land a page to enter username and password to access your back-end. As you can guess, this is not normal visitor’s behavior. This is a suspicious activity.
Our website security system’s 404 error detection takes advantage of the suspicious activity.
here is how it works.
If every time someone landed non-existed page and received 404 error, we take notes. And this person hits 404 error too many times, we blacklist this person’s IP address and ban this person from visiting your website.