强制使用解析器并禁用回退

Question

I want to achieve resolving a given domain by the DNS Server I provide.

The code below I've grabbed from https://play.golang.org/p/s2KtkFrQs7R The result is giving the correct results - but unfortunately even when I'm giving an IP like 123.123.123.123:53 as the resolver IP...

I guess there's a fallback - but I could not find (https://golang.org/pkg/net/) the switch to turn it off...

Thanks in advance for any hint...

Matthias

package main

import (
    "context"
    "fmt"
    "log"
    "net"
    "time"
)

func GoogleDNSDialer(ctx context.Context, network, address string) (net.Conn, error) {
    d := net.Dialer{}
    return d.DialContext(ctx, "udp", "123.123.123.123:53")
}

func main() {
    domain := "www.google.com"
    const timeout = 1000 * time.Millisecond
    ctx, cancel := context.WithTimeout(context.TODO(), timeout)
    defer cancel()
    // var r net.Resolver
    r := net.Resolver{
        PreferGo: true,
        Dial:     GoogleDNSDialer,
    }

    records, err := r.LookupHost(ctx, domain)

    if err != nil {
        log.Fatal(err)
    } else {
        fmt.Printf("Records %v 
", records[0])
    }

}