Scenario: A Citrix Administrator has configured the Citrix ADC as a DNS Proxy Server.

The commands in the screenshot create a responder action and policy that modify the DNS response from the Citrix ADC to the client. The responder action uses the DNS.NEW_RESPONSE function, which creates a new DNS response with the specified parameters. The first parameter is true, which means the response will have the TC (truncated) bit set. The second parameter is true, which means the response will have the AA (authoritative answer) bit set. The third parameter is NOERROR, which means the response will have the rcode (response code) set to NOERROR. The responder policy matches the DNS requests that use UDP as the transport protocol and applies the responder action to them. Therefore, the effect of this configuration is to create a DNS response with TC bit set and rcode as NOERROR for UDP requests. This can be used to prevent DNS amplification attacks by limiting the size of the DNS response.