Common Web Page Errors

To an advanced webmaster, this guide is redundant. To an aspiring webmaster, this guide will outline the most common web page errors you may encounter.
 
HTTP status codes are three-digit numbers that provide Web browsers with information about the page's status. You might see some of these errors while browsing the Internet, or you might have received them in your own hosting account.

Here's a quick list to help you understand the most common error codes with suggestions for what to do to fix the error:
 
400 — Bad Request
The Web server couldn't parse a malformed script. Most often, programming problems cause this issue. You should talk to your developer or software provider for help resolving this issue.
 
401 — Authentication Required
This page requires a user name and password to access it. If you try to access it without it, you get a 401 — Authentication Required message.
 
403 — Forbidden
Forbidden errors display when somebody tries to access a directory, file, or script without appropriate permissions. For example, if a script is readable only to the user and others cannot access the file, they'll see a 403 error.

Invalid index files and empty directories can also cause 403 errors.
 
404 — Not Found
If visitors access URLs that don't exist, they receive 404 errors. The cause can be anything from invalid URLs, missing files, or redirects to URLs that no longer exist.
 
500 — Internal Server Error
This is a very general error that means there's a problem with the website displaying, but the details aren't readily available. Invalid .htaccess files, or invalid rules in them, commonly cause 500 errors with Linux based hosting accounts. With Windows based hosting accounts, it's most commonly invalid requests through a web.config file.

To find out what causes the issue:

• Linux — Review your Apache® error logs.
• Windows — Enable detailed errors in your web.config file.

  For more information, check out the list of status code definitions at W3.org:

http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html