Add NSID description to README.md.
@@ -40,6 +40,7 @@ Currently CoreDNS is able to:
* Provide metrics (by using Prometheus) (*metrics*).
* Provide query (*log*) and error (*error*) logging.
* Support the CH class: `version.bind` and friends (*chaos*).
+* Support the RFC 5001 DNS name server identifier (NSID) option (*nsid*).
* Profiling support (*pprof*).
* Rewrite queries (qtype, qclass and qname) (*rewrite*).
* Echo back the IP address, transport and port number used (*whoami*). This is also the default
