Define External DNS Server elements
There are some cases in which you must define an External DNS Server element.
- (Engines only) For dynamic DNS (DDNS) updates with a Multi-Link configuration.
- (Engines only) If you want to use a DNS server for resolving malware signature mirrors.
- If you want to use a DNS server for resolving domain names and URL filtering categorization services on Engines.
You can also optionally use External DNS Server elements to specify the DNS servers to which the Engine forwards DNS requests when you configure DNS relay.
If the device has additional IP addresses, you can enter them as secondary IP addresses instead of creating additional External DNS Server elements. However, secondary IP addresses are only used in the Source and Destination cells in rules. They are ignored otherwise.