blockResponse 
  The way that you want DNS Firewall to block the request, used with the rule action setting BLOCK.
- NODATA- Respond indicating that the query was successful, but no response is available for it.
- NXDOMAIN- Respond indicating that the domain name that's in the query doesn't exist.
- OVERRIDE- Provide a custom override in the response. This option requires custom handling details in the rule's- BlockOverride*settings.
This setting is required if the rule action setting is BLOCK.