quick and dirty test dns server with different negative rcodes

baddns.go

package main

import (
	"fmt"

	"github.com/miekg/dns"
)

func negrcode(w dns.ResponseWriter, r *dns.Msg) {
	m := new(dns.Msg)
	m.Authoritative = true
	fmt.Printf("QUESTION\n%+v\n", r)
	switch r.Question[0].Qtype {
	case dns.TypeAAAA:
		m.SetRcode(r, dns.RcodeYXDomain)
	case dns.TypeA:
		m.SetRcode(r, dns.RcodeNotZone)
	case dns.TypeCNAME:
		m.SetRcode(r, dns.RcodeNotAuth)
	default:
		m.SetRcode(r, dns.RcodeNotImplemented)
	}
	fmt.Printf("REPLY\n%+v\n", m)
	if err := w.WriteMsg(m); err != nil {
		fmt.Printf("REPLY ERROR: %v\n", err)
	}
}

func main() {
	dns.HandleFunc("home.arpa.", negrcode)
	server := &dns.Server{Addr: "[::]:53", Net: "udp", TsigSecret: nil}
	if err := server.ListenAndServe(); err != nil {
		fmt.Printf("Failed to setup the udp server: %s\n", err.Error())

	}
}