DNS fallback definition
DNS fallback is a mechanism where a client or resolver attempts to use an alternative DNS server or resolution method when the primary DNS resolver fails entirely, such as due to a server crash or network failure. This process ensures continued service availability and resilience against outages by automatically redirecting DNS queries to a working alternative, maintaining seamless website connectivity even when primary systems encounter issues.
See also: DNS failover, DNS load balancing
How it works
- A device that needs to resolve a domain name sends a query to a designated primary DNS resolver.
- If this primary resolver fails to respond or experiences an outage, the system falls back to a pre-configured secondary or tertiary DNS resolver.
- The DNS failover system runs regular health checks on DNS resolvers to ensure that servers are available.
- The failover mechanism automatically changes the IP addresses given out in public DNS to redirect traffic away from failed servers to operational ones.
Benefits
- Enhanced high availability and reliability for websites and services.
- DNS fallback acts as a safety mechanism during server breakdowns.
- Traffic can be redirected to backup servers automatically, keeping websites and services online.
- Organizations that provide DNS fallback mechanisms help ensure continuous DNS protection for networks, safeguarding DNS resolution even during outages.
