Why Use Custom 404 Pages?

Custom 404 error pages are not only important as sound SEO practice but also for increased visitor retention as well, and we all want to keep our visitors, now don’t we?

The 404 or Not Found error message is a standard HTTP response code that indicates when the client was able to communicate with the server but the server could not find what was requested. When a 404 is received on IIS the default settings will map the response to serve a Microsoft default 404 error page.

Webservers can be configured to display a customized error page; however, some browsers will not display this page unless they are larger than 512 bytes in size. When this happens, some browsers will replace too small pages with special 404 pages of their own. This is something that you will want to avoid; it doesn’t help your site and may just lead visitors away from your site.

People surfing to your website via a Google search or a link from another site will find it very frustrating if they come upon a generic 404 error page that shows no way to find the information they were seeking. A common problem in larger sites with complex site architecture are when pages are moved or file  or directory names changed without a 301 redirect put in place.

When someone is visiting a website and encounters a generic 404 page they will either:

a. Click on the [Back] button on their browser and try a different site.
b. Try to back up one directory in the site’s URL.
c. Write to the webmaster and make them aware of the missing page.

Personally, I’d put my money on “A”. Most people’s instinct is to just hit the Back button. It does not occur to most that they can solve the problem by choosing “B”, and they usually don’t care enough, nor have the time to choose “C”.

By building a custom 404 error page you not only catch the holes in your site architecture, but you also help to keep the potential customers that found your site. A good custom error page should consist of at the very least site navigation so that the visitor can surf to another part of your site and find what they came looking for. An even better custom error page would serve as a means to motivate the visitor in a certain direction. For instance, let’s say you really want visitors to read your blog or see the latest product that your company if offering, the custom error page can do that.

From a security perspective, when your web server dumps a generic 404 (or any other error message for that matter) it might be telling your visitors more information than they ever really wanted to know, and hackers information they’d love to see. Don’t be too nice or too descriptive in error handling messages on the public side, or you may be exposing a larger attack surface to hackers.

How to Create a Custom 404 Error Page in Microsoft IIS

1. Create Your Custom 404 Error Page - Use a text editor or an HTML editor to create your custom page on your server. You can name it anything you wish. (i.e. /404-error-page.htm or /not-found.htm). 
2. Open Internet Service Manager - From the server desktop, launch the Internet Services Manager (usually located at Start->Programs->Administrative Tools->Internet Services Manager)
3. Click the [+] to the left of the server name
4. Right-click on “Default Web Server” (or whatever you have named it), and click on “Properties”
5. Locate the Custom Errors Tab - Click on the Custom Errors tab.
6. Identify the Error that you would like to edit – Select 404 from the list and click “Edit Properties”. 
7. Use the Browse button to locate the custom file you created (i.e. /not-found.htm) and click OK. Keep clicking OK to dismiss the windows; close Internet Service Manager.

On a lighter note, if you have the time take a visit to 404 Research Lab, a site devoted to nothing but error pages, with a huge gallery of examples good, bad, cute, and crude. Pick up some useful hints, find out who invented the 404 error page, or read their loving tribute to error pages as peaceful oases.

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