DNS response times that are consistently longer than two seconds typically indicate that one of the DNS servers is not responding.
When a Time To Live (TTL) value expires for a Domain Name Server (DNS) record on a node, the BIND service on the node (DNS service) performs a full lookup from a DNS root server. The node will attempt to obtain information from the first DNS server in the list. If a response is not received in 2 seconds, the node tries the next DNS server in the list, and so on.
If you have concerns about the DNS times, or the lookup appears to be directing to a DNS server abnormally far away from the node you are using, contact Customer Support for additional troubleshooting.