Name Server Identifier (NSID)

Knot Resolver provides server-side support for RFC 5001 which allows DNS clients to request resolver to send back its NSID along with the reply to a DNS request. This is useful for debugging larger resolver farms (e.g. when using multiple instances of Knot Resolver, anycast or load balancers).

NSID value can be configured in the resolver’s configuration file:

nsid: kres1


When running with multiple workers, each worker adds its own identifier to the end of the NSID.