Provide DNS Infrastructure/Traffic Services, such as, Load Balancing, Caching, and Logging for Telecom Service Providers
Telecom service providers can configure the Citrix ADC appliance to function as a DNS proxy. Caching of DNS records, which is an important function of a DNS proxy, is enabled by default on the Citrix ADC appliance. This enables the Citrix ADC appliance to provide quick responses for repeated translations and hence enhances the customer experience and also saves the bandwidth. The caches responses from DNS name servers. When the appliance receives a DNS query, it checks for the queried domain in its cache. If the address for the queried domain is present in its cache, the Citrix ADC appliance returns the corresponding address to the client. Otherwise, it forwards the query to a DNS name server that checks for the availability of the address and returns it to the Citrix ADC appliance. The Citrix ADC appliance then returns the address to the client.
For requests for a domain that has been cached earlier, the Citrix ADC appliance serves the Address record of the domain from the cache without querying the configured DNS server and hence saves the bandwidth.
From 11.0 release onwards, Citrix ADC also logs the DNS requests that it receives and also the responses that it sends to the client. Telecom service providers can use this log to:
- Audit the DNS responses to the client
- Audit DNS clients
- Detect and prevent DNS attacks
For more information, see Domain Name System.