Why Does WAF Block Normal Requests as Invalid Requests?

Symptom

After a website is connected to WAF, a normal access request is blocked by WAF. On the Events page, the corresponding Event Type reads Invalid request, and the Handle False Alarm button is grayed out, as shown in Figure 1.

Figure 1 Normal requests blocked by WAF as invalid requests

Possible Cause

If either of the following numbers in an access request exceeds 512, WAF blocks the access request as an invalid request:
  • Number of parameters in a form when form-data is used for POST or PUT requests
  • Number of URI parameters

Solution

If you confirm that the blocked request is a normal request, allow it by referring to Configuring a Precise Protection Rule.

Parent topic: Service Interruption Check