// Retrieve the MX records for miek.nl.
func ExampleMX() {
config, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
c := new(dns.Client)
m := new(dns.Msg)
m.SetQuestion("miek.nl.", dns.TypeMX)
m.RecursionDesired = true
r, _, err := c.Exchange(m, config.Servers[0]+":"+config.Port)
if err != nil {
return
}
if r.Rcode != dns.RcodeSuccess {
return
}
for _, a := range r.Answer {
if mx, ok := a.(*dns.MX); ok {
fmt.Printf("%s\n", mx.String())
}
}
}
// Retrieve the DNSKEY records of a zone and convert them
// to DS records for SHA1, SHA256 and SHA384.
func ExampleDS(zone string) {
config, _ := dns.ClientConfigFromFile("/etc/resolv.conf")
c := new(dns.Client)
m := new(dns.Msg)
if zone == "" {
zone = "miek.nl"
}
m.SetQuestion(dns.Fqdn(zone), dns.TypeDNSKEY)
m.SetEdns0(4096, true)
r, _, err := c.Exchange(m, config.Servers[0]+":"+config.Port)
if err != nil {
return
}
if r.Rcode != dns.RcodeSuccess {
return
}
for _, k := range r.Answer {
if key, ok := k.(*dns.DNSKEY); ok {
for _, alg := range []uint8{dns.SHA1, dns.SHA256, dns.SHA384} {
fmt.Printf("%s; %d\n", key.ToDS(alg).String(), key.Flags)
}
}
}
}
func (d dnsAPI) Recurse(w dns.ResponseWriter, req *dns.Msg) {
var client dns.Client
if isTCP(w.RemoteAddr()) {
client.Net = "tcp"
}
for _, recursor := range d.Recursors {
res, _, err := client.Exchange(req, recursor)
if err != nil {
continue
}
w.WriteMsg(res)
return
}
// Return SERVFAIL
res := &dns.Msg{}
res.RecursionAvailable = true
res.SetRcode(req, dns.RcodeServerFailure)
w.WriteMsg(res)
}