Learn about the 404 error page, causes and basic solutions. Better yet, learn how to prevent the dreaded 404.
All of us have seen them at some point: the 404 error page. Worse yet, if you are a webmaster, you may have had one or more of your very own.
To the new webmaster, 404 errors on your site are too often a source of workplace comedy, horror and chronic low self-esteem.
404 pages occur when a link brings our visitor to an unknown page. Typos, error in a URL, or a link to a web page that has been moved, deleted or changed have all been known to cause the dreaded 404.
Why Does This Happen? Is There No Justice?
There are several reasons that your site visitors may receive a 404 error page. But, simply said, the 404 means that the clicked link does not point to a valid target (page or document).
Another way to think about it is that a link and a target are two completely different things. If these two objects do not agree by having the same address (URL), the result is a 404 error.
Because the web is a distributed medium (a link and a target may be physically separated by thousands of miles), there is no good, automatic mechanism for ensuring that links to a page or document also change along with the target of that link.
Of course, there are some exceptions such as automated navigation in Center Stage CMS or WordPress, but cross-site links and manually created links will nearly always need periodic, post-launch validation.
Starting out, the new webmaster only has a few pages and documents to worry about. As your site grows and ages, “link rot” becomes a much larger problem and may require daily intervention.
What happens when our hero, the site webmaster changes the name of a page?
In many CMS systems or in a static site, changing the name of a page, will often change the URL to the page or document. If any one of the links pointing to this page are not also updated, a visitor will receive a 404 page when clicking on the link.
What about changing the name of a folder or a “parent folder”? What is a parent folder? A parent folder most often defines the “path” to the page. This path is the part of the url between the domain name and the page name.
Any wrong turn on that path results in a 404 error.
In most static systems, changing the name of a folder will often also change the URL to the page or document. If any one of the links pointing to this page are not also updated, a visitor will receive a 404 page when clicking on the link.
Naturally there are tools that rebuild links when you are editing a static page, but in the CMS world such as Center Stage and WordPress, the concept of the “Permalink” has evolved to help.
Read more about Permalinks on Wikipedia.
Solving the Problem: Fixing a 404 Error
If the 404 error is caused by a missing page or document on another site.
Link Fix: Correct or remove your bad link.
Note: If you choose to keep it, check this link periodically. It can and probably will fail again.
If the 404 error is caused by a bad link on another site.
Link Fix: Contact the other site owner, letting them know you have a new target url for that link. Give them the new url and ask them nicely to fix the link. Wait.
Target Fix: Put the page or document at the address.
But wait… if you already have the document at another location, you’ll have another problem – the dreaded duplicate, but out-of-sync content problem.
There is a better way: create a “redirect” on your site. Coming up next.
If the 404 error is caused by a problem on your site, you have one of two solutions:
Link Fix: Correct or remove the bad link(s).
Target Fix: Replace or redirect the missing page or document.
Redirects – Signposts of the Web
A redirect is Webmaster jargon for a web server “forward order”. Similar to a Post Office forward order, a redirect is record or configuration directive that tells the server to inform browsing software this:
The target you are looking for is no longer here. It has moved. Here is the new URL.
Finally, the redirect may be permanent or temporary. Most redirects are permanent, but temporary redirect orders may be necessary during a global server reorganization, reconfiguration or temporary outage.
The Search Engine Optimization implications of a redirect are significant. Most SEO observers believe that Google and other search engines will retain and transfer the historical pagerank (or equivalent mojo) from the old address to the new one.
Like Grandpa always said, “Check Your Links”
Back in the good old days, webmasters would check their links by clicking.
This would be the tedious, stats-inflating, error-prone way. “And we liked it!”, they would say to earnest young webmasters at their knee.
With today’s large websites containing hundreds of external links. A better option is to purchase desktop software that would check the links and report any broken or malfunctioning links. However, this also time-consuming, inflates stats, and takes server processing away from your visitors.
Today, the enlightened webmaster simply gathers analytics using a custom 404 page. More about this next week.