PERL CGI Tutorial
for Writing Interactive Form Scripts

Access Log and Error Codes

Access Log

The access log can be a valuable tool in the management of your web site.

It can tell you:

  • what pages are not functioning properly.
  • where your traffic is coming from.
  • what pages are visited the most.
  • if you are visited by robot spiders.
  • if someone bookmarks your site.
  • your peak days and hours of traffic.

You can get some of this information through a stat service, but the really interesting stuff you will have to do yourself.

For instance if you see a request for a file named favicon.ico, it means someone bookmarked your site using an Explorer browser.

If you see a request for robot.txt or robots.tx it may mean that you were visited by a search engine spider.

If you see a lot of 304 status codes it means that users are bookmarking and revisiting your site.

If you have a most wanted response by your users, you can study the path that each user took to reach that response.

For example if your mwr is for a user to download a file, you would study the path each took before downloading and look for a pattern.

This could help you to enhance the content of the pages that were accessed and eliminate the unused.

Error Codes

The Apache server will report errors and status by a numerical code in the access log.

The most common are:

  • 200 - OK
  • 204 - No Response
  • 206 - Incomplete Transaction
  • 301 - Moved Permanently
  • 302 - Found
  • 303 - See Other
  • 304 - Revisit to Cached Page
  • 307 - Temporary Redirect
  • 400 - Bad Request
  • 401 - Unauthorized request
  • 403 - Forbidden
  • 404 - Not Found
  • 405 - Not Allowed
  • 408 - Request timed out
  • 500 - Internal server error
  • 503 - Service unavailable
  • 504 - Gateway timed out

Take immediate action when you see the codes marked in red appearing in your access log on your internet web space..