The 404 code (not found) indicates:
URL is incorrectly written by the visitor. This could be due to a URL wrongly typed or a deliberate intent to search for hidden pages or security holes in our website (which could be described as "pre-attack").
URL that does not exist in our website (dead links).
Identifying the source IP of these movements can help to perform protective measures, if necessary.
There is a certain percentage of cases where the referrer is the own website (www.logcasts.com). This means that the user is trying unsuccessfully to access a particular web resource addressed by the website itself and indicates that there is some kind of problem on that link. This might indicate that the website contains dead links or typos. When the referrer is external to our website, it might indicate either wrong links or potential attacks looking for vulnerable pages.