Having a secondary DNS server is a good practice for redundancy and fault tolerance in case your primary DNS server goes down. This is especially important if you rely on your DNS server for network connectivity and service accessibility.
Here are some points to consider regarding the use of primary and secondary DNS servers:
1. Redundancy: If your primary DNS server becomes unavailable for any reason, having a secondary DNS server ensures that your devices can still resolve domain names and access network resources. This helps prevent interruptions in connectivity.
2. Load Balancing: By distributing DNS queries between a primary and secondary server, you can share the load and prevent a single server from becoming overwhelmed, leading to better performance and reliability.
3. Device Behavior: Devices typically use the primary DNS server for resolving domain names. If the primary server is unavailable, devices will then switch to using the secondary DNS server. This failover mechanism ensures continuous DNS resolution even if the primary server is down.
4. Configuration: You can configure your devices to use both the primary and secondary DNS servers simultaneously, with the secondary server serving as a backup. This way, if the primary server fails to respond, the device can quickly switch to the secondary server for DNS resolution.
In your setup with AdguardHome running on an Orange Pi One, setting up a secondary DNS server on another Orange Pi One can provide additional reliability. You can configure your devices to use both DNS servers, with the secondary server acting as a failover in case the primary server becomes unavailable.
Overall, while having a secondary DNS server is not strictly necessary, it is a good practice to ensure continuous availability of DNS services and prevent connectivity issues in case of a primary server failure.
