The SDNS_DEBUGNS environment variable is beneficial for verifying the RTT (Round Trip Time) of authoritative servers. To use it, send an HINFO query for zones with chaos class.
In sdns, you have the ability to add custom plugins. The sequence of the plugins and the middlewares has a mutual impact on their execution. Config keys must be strings, and values can be of any type. Plugins are loaded before the cache middleware in the specified order.