The symptoms of an overloaded web server are:
- Requests are served with (possibly long) delays (from 1 second to a few hundred seconds).
- The web server returns an HTTP error code, such as 500, 502, 503, 504, 408, or even 404, which is inappropriate for an overload condition.
- The web server refuses or resets (interrupts) TCP connections before it returns any content.
- In very rare cases, the web server returns only a part of the requested content. This behavior can be considered a bug, even if it usually arises as a symptom of overload.