DNS reflector server in GO

April 4, 2011


I’m (again) rewriting the API of godns. I’ve now taking a cue from the http package in Go, the result seems very nice. A reflector (returns your query in the answer) in Go becomes:

package main

import (

func ReflectServer(w dns.ResponseWriter, req *dns.Msg) {
        m := new(dns.Msg)

        m.Extra = make([]dns.RR, 1)
        m.Extra[0] = &dns.RR_TXT{Hdr: dns.RR_Header{Name: m.Question[0].Name, Rrtype: dns.TypeTXT, 
                Class: dns.ClassINET, Ttl: 0}, Txt: "Hello world"}
        buf, _ := m.Pack()

func main() {
        dns.HandleFunc(".", ReflectServer)
        err := dns.ListenAndServe(":8053", "udp", nil)
        if err != nil {
                log.Fatal("ListenAndServe: ", err.String())