The HTTP Service performance object in Performance Monitor includes a counter that displays not-found errors. Not-found errors are client requests that could not be satisfied because they included a reference to a Web page or a file that did not exist.
Many not-found errors occur because Web pages and files are deleted or moved to another location. However, some might result from user attempts to access documents that they are not authorized to have.
You can use the HTTP Service: Not Found Errors counter to track the number of not-found errors on your server. You can also set a Performance Monitor alert to notify the Administrator when the number of not-found errors exceeds a threshold.
Following is a brief description of the HTTP Service: Not Found Errors counter.
Table 8.2 Performance Monitor Counter for Not-Found Errors
Counter | Indicates |
HTTP Service: Not Found Errors | The number of client read requests that could not be satisfied because the URL did not point to a valid file. Increases in not-found errors might indicate that a file has been moved without its link being updated. However, it might also indicate failed attempts to access protected documents, such as user lists and file directories. |