But not all web sites behave that way. For example, if you enter a bad URL at Goggle.com (type a forward slash after the “.com” followed by a bunch of gibberish), you’ll get the expected “The page cannot be found” page. But try the same thing at Ipswitch.com, and you’ll never see a 404 error — instead you’ll be directed to the site’s home page. Microsoft.com escorts lost browsers to a linked Site Map.

Redirect Yourself

The HTTP at the beginning of web addresses stands for HyperText Transport Protocol. When something goes wrong with an HTTP address, it triggers a HyperText Transport Protocol error, which are numbered 100 through 505. Errors 400 through 505, of which 404 is the most common, are “configurable,” meaning the webmaster or system administrator can control how the web server responds to the error.

Apache, the most popular web server software, handles HTTP errors using a small text file, .htaccess, located in the public_html directory. The redirection syntax is straightforward:

ErrorDocument [error code] [url]

The URL following the error code can point to a valid page at any valid address. Usually, it points to a customized page in the site’s home directory:

ErrorDocument 404 /404error.html

But if you pointed the URL to the home page address (typically, index.html), then a 404 error would redirect the user to the site’s home page and no error page would be displayed. This is what Ipswitch.com does:

ErrorDocument 404 /index.html

Common HTTP Error Codes

Most common configurable HTTP errors:

400: Bad Request
The server does not understand the query sent by your browser.

403: Forbidden
You don’t have permission to access that address (URL) on this server.

404: Not Found
The address (URL) your are searching for was not found on the server.

412: Precondition Failed
The preconditions necessary to fulfill the request have not been met.

500: Server Error
The server was unable to fulfill the request because of an internal error.

501: Not Implemented
The functions required to fulfill the request have not been implemented on this server

503: Service Unavailable
The requested service is unavailable on this server.

Serve and Volley

The instructions above apply to Apache servers. The 404 error page on Microsoft IIS web servers can be changed by selecting the web site directory in Internet Information Services, clicking on Properties, selecting the Custom Errors property sheet, selecting the error message you would like to change, and then editing the path to the modified file. If your web hosting service uses a different program, your web host administrator should be able to provide the necessary details for modifying a 404 error page.

In fact, creating 404 error pages has become something of an art itself. Entire web sites have been devoted to inventive 404 error pages. A good place to start is the “404 Research Lab”.

Microsoft Gets Friendly

These days, the cost of running your own web site can be as low as $.10 a day, so anybody can be a webmaster. (ICANN registrar Catalog.com, for example, will host a minimal site for the cost of registering the domain.) All you need is a few free utilities (e.g., HTML-Kit, from Chami.com, WS-FTP LE, from Ipswitch.com), and you’re ready to put your digital presence online. So you edit the .htaccess file to direct bad URLs to your incredibly user-friendly 404 error page, FTP it to your site, test it out, and what happens?

“The page cannot be found”

“The page cannot be found” error is generated by Internet Explorer, not the web server. Microsoft’s rational is that the default HTTP error message is neither helpful nor useful, and they are right. The default 404 HTTP error message reads, in total:

404 Not Found
The requested URL was not found on this server

No other information is included. There is no redirection, and no other instructions. The Microsoft version is more helpful, though it looks like the small print in a legal document, and can turn people away as quickly as they arrive.