Make DNS-Request Routes actually use the additional DNS-Servers specified
When creating a DNS request route via Network -> DNS -> DNS request route, one may specify a list of hosts to be queried for this specific DNS-domain. According to the UI, the order of this list indicates priority of the servers.
However, should the first server fail to reply (because it is down or unreachable), NO other DNS-server will be queried. According to Sophos Support, this is the intended behavior as the additional Servers are only queried if the first server replies with NXDOMAIN.
This is obviously not usable as a failover scenario and is certainly not the behavior expected by customers.
If the request to the first server times out, additional servers should be queried.