404 errors are caused by requests to pages or resources that don't exist on the server. What this can mean, is each time someone mistypes a URL, your
application is going to query the database to try to figure out if that
page exists, and if it doesn't it is going to serve up a page not found
error to the visitor.
In most cases this type of default 404 error page activity is completely harmless. However if you are getting a lot of 404 errors, it can become more and more problematic.
Causes of 404 errors
Let's take a look at some of the most common reasons a 404 error might be generated.
- A visitor tries to manually type in a page that doesn't exist.
- Your pages were not internally or externally linked correctly in the first place.
- Resources such as images, .css, .js, or other files were removed from the server.
- One of your pages was moved, and links either internal or external weren't updated.
- Search engine crawlers, or automated bots try to access generic pages that your site doesn't have.
404 error page handling
A good webmaster will want to periodically check on their website statistics to see what requests are generating the most 404 errors.
You can use this information to your advantage. Let's say for example you notice 500 people a month are trying to pull up a page called /about that doesn't exist. You can go ahead then and create that page, or setup re-direction on that URL to hopefully get them pointed in the right direction and have them remain on your site during future visits.
Statistics on 404 errors can be tracked in AwStats on your cPanel. Once you access Awstats, scroll to the very bottom of your statistics report. You should see the total number of 404s encountered and what percentage of your traffic that represents. Then simply click on the 404 link to see the actual requests triggering these errors.