Does CSM support load balancing of DNS requests?
A. As of CSM release 2.1(1) the CSM supports load balancing of UDP flows, including DNS. Some implementations generate requests with both source and destination ports equal to 53: this is not an issue, since a flow is identified on both client and server side on the entire 5-tuple (plus other information). Consider that the CSM does not have ALG (Application Layer Gateway) functionality for DNS, so the CSM cannot change any information in the application layer of the packets. The CSM can change L4 ports and L3 information, but the content of a DNS reply from the real DNS servers cannot be modified.