NAT support for DNS

You can use DNS and a fully qualified domain name (FQDN) with either source NAT or destination NAT as part of your NAT configuration. You can use DNS name servers to resolve hostnames to IP addresses. A DNS cache time to live (TTL) is introduced under the address-book option for each DNS name entry. We support a minimum DNC cache TTL of 16 seconds. In case of multiple IP addresses in the DNS response, the first IP address in the response is added to the NAT pool.