Domain name servers (DNS) are used to translate domain names to IP addresses. If the DNS server that supports your organization is down, multiple services, such as mail servers, web sites, or proxy servers may be unavailable to the outside world.
DNS monitoring provides consistent connectivity to your websites and servers, saving you time when diagnosing DNS issues. DNS monitoring ensures your critical services are always up and running.
Slow DNS resolution can translate to sluggish website performance. Our DNS monitoring solution can test DNS resolution by directly querying specified servers or propagating Internet root servers to resolve a specific Internet address from multiple points around the world.
Device Cached. This is the default option and means the cached name server (NS) address retrieved during monitoring of a previous task (device cache) will initially be used for monitoring. If the device cache does not have the needed address, then an automatic inquiry for the address from root DNS servers will be conducted.
Non-cached. The device cache (cache of preceding tasks) will not be used, so each new execution demands a separate inquiry to DNS root servers. This is useful for ensuring uniform times since the DNS lookup will be performed each time.
TTL Cached. NS cache formed during monitoring of preceding tasks (device cache) will initially be used for monitoring. If the device cache does not have the needed address, then an automatic inquiry for the address will be conducted from the local DNS server.
External DNS Server. A specified IP address will be considered as a DNS server address and polled for NS data. For example, this is useful in situations where most of your clients use a public caching service.
For more information on DNS mode options, please visit our Knowledge Base page.