DNS query through 5353 non-standard port

dns-query-test.go

package main
/* DNS query through 5353 non-standard port */

import (
	"time"
	"github.com/miekg/dns"
	"encoding/binary"
	"net"
	"fmt"
)

func Dnstest(target string, server string, timeout_secs int) uint32  {
    c := dns.Client{Net: "udp4", Timeout: time.Duration(timeout_secs) * time.Millisecond}
    m := dns.Msg{}
    m.SetQuestion(target+".", dns.TypeA)
	m.RecursionDesired = true
    r, _, err := c.Exchange(&m, server)
    if err != nil {
        // fmt.Println(err)
		return 0
    }
    // fmt.Printf("Took %v\n", t)
    if len(r.Answer) == 0 {
        // fmt.Println("No results")
		return 0
    }
    for _, ans := range r.Answer {
        Arecord := ans.(*dns.A)
        // fmt.Printf("%s\n", Arecord.A)
		return Ip2long(Arecord.A.String())
    }
	return 0
}

func Ip2long(ipstr string) uint32 {
	ip := net.ParseIP(ipstr)
	if ip == nil {
		return 0
	}
	ip = ip.To4()
	return binary.BigEndian.Uint32(ip)
}

func Do_test(Domain_str string, Srv_str string) bool {
	if Dnstest(Domain_str, Srv_str, 5000) > 0 {
		return true
	} else {
		return false
	}
}


func main() {
	Domain_str := "google.com"
	var Title_str string
	var Srv_str string

	// CERTNET
	Title_str = "CERTNET:"
	Srv_str = "202.141.162.123:5353"
	fmt.Println(Title_str, Srv_str, Do_test(Domain_str, Srv_str ) )
	Srv_str = "202.38.93.153:5353"
	fmt.Println(Title_str, Srv_str, Do_test(Domain_str, Srv_str ) )

fmt.Println("")

	// openDNS
	Title_str = "openDNS:"
	Srv_str = "208.67.222.222:5353"
	fmt.Println(Title_str, Srv_str, Do_test(Domain_str, Srv_str ) )
	Srv_str = "208.67.220.220:5353"
	fmt.Println(Title_str, Srv_str, Do_test(Domain_str, Srv_str ) )

fmt.Println("")

	// AdGuard DNS
	Title_str = "AdGuard DNS:"
	Srv_str = "176.103.130.130:5353"
	fmt.Println(Title_str, Srv_str, Do_test(Domain_str, Srv_str ) )
	Srv_str = "176.103.130.131:5353"
	fmt.Println(Title_str, Srv_str, Do_test(Domain_str, Srv_str ) )
	Srv_str = "176.103.130.132:5353"
	fmt.Println(Title_str, Srv_str, Do_test(Domain_str, Srv_str ) )
	Srv_str = "176.103.130.133:5353"
	fmt.Println(Title_str, Srv_str, Do_test(Domain_str, Srv_str ) )
	Srv_str = "176.103.130.134:5353"
	fmt.Println(Title_str, Srv_str, Do_test(Domain_str, Srv_str ) )
}