case "MX":
			_, err := r.LookupMX(context.Background(), req)
			return err
		case "NS":
			_, err := r.LookupNS(context.Background(), req)
			return err
		case "NetIP":
			_, err := r.LookupNetIP(context.Background(), "ip", req)
			return err
		case "SRV":
			const service = "service"
			const proto = "proto"
			req = req[len(service)+len(proto)+4:]