diff --git a/cmd/domain.go b/cmd/domain.go
deleted file mode 100644
index 85a7644..0000000
--- a/cmd/domain.go
+++ /dev/null
@@ -1,25 +0,0 @@
-package cmd
-
-import (
-	"github.com/spf13/cobra"
-)
-
-var input string
-var output string
-var domainCmd = &cobra.Command{
-	Use:   "domain",
-	Short: "query the ip and nameserver information",
-	Long:  "query the ip and nameserver information",
-	Run:   getDomainInfo,
-}
-
-func getDomainInfo(cmd *cobra.Command, args []string) {
-
-}
-
-func init() {
-	domainCmd.Flags().StringVarP(&input, "input", "i", "", "")
-	domainCmd.Flags().StringVarP(&output, "output", "o", "", "")
-	domainCmd.MarkFlagsRequiredTogether("input", "output")
-	rootCmd.AddCommand(domainCmd)
-}
diff --git a/cmd/query.go b/cmd/query.go
new file mode 100644
index 0000000..5838bb1
--- /dev/null
+++ b/cmd/query.go
@@ -0,0 +1,106 @@
+package cmd
+
+import (
+	"dtool/utils"
+	"fmt"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/spf13/cobra"
+)
+
+// input parameters
+// var query_target string
+var query_port string
+var query_name string
+var query_type uint16
+var query_class uint16
+var query_rate int
+var query_packets int
+var query_random_prefix bool
+
+/*
+DNS请求测试功能，可设置参数包括域名（随机前缀），资源记录type/class，请求速率，请求数量
+*/
+var queryCmd = &cobra.Command{
+	Use:   "query",
+	Short: "",
+	Long:  "",
+	Run:   queryTest,
+}
+
+func concurrent_request(ip, domain, port string, qtype, qclass uint16, result chan int, wg *sync.WaitGroup) {
+	wg.Add(1)
+	res, err := utils.SendQuery(ip, domain, port, qtype, qclass)
+	if err != nil {
+		result <- (-1)
+		//fmt.Println(err)
+	} else {
+		rcode := utils.ParseRcode(res)
+		result <- rcode
+	}
+	wg.Done()
+}
+
+func response_stat(stat []int, result chan int, wg *sync.WaitGroup) {
+	wg.Add(1)
+	defer wg.Done()
+	for {
+		if v, ok := <-result; ok {
+			switch v {
+			case 0:
+				stat[0]++
+			case 2:
+				stat[1]++
+			case 3:
+				stat[2]++
+			case -1:
+				stat[3]++
+			default:
+				stat[4]++
+			}
+		} else {
+			break
+		}
+	}
+}
+
+func queryTest(cmd *cobra.Command, args []string) {
+	var wg1 sync.WaitGroup
+	var wg2 sync.WaitGroup
+	result := make(chan int)
+	stat := make([]int, 5)
+	if len(args) == 1 {
+		if utils.IsValidIP(args[0]) {
+			timestamp := strconv.FormatInt(time.Now().Unix(), 10)
+			go response_stat(stat, result, &wg2)
+			for i := 0; i < query_packets; i++ {
+				var qname string
+				if query_random_prefix {
+					qname = strings.Join([]string{timestamp, strconv.Itoa(i)}, "-") + query_name
+				} else {
+					qname = query_name
+				}
+				go concurrent_request(args[0], qname, query_port, query_type, query_class, result, &wg1)
+				time.Sleep(time.Second / time.Duration(query_rate))
+			}
+			wg1.Wait()
+			close(result)
+			wg2.Wait()
+			fmt.Printf("total: %v noerr: %v servfail: %v nx: %v error: %v other: %v\n", query_packets, stat[0], stat[1], stat[2], stat[3], stat[4])
+		}
+	}
+}
+
+func init() {
+	queryCmd.Flags().BoolVarP(&query_random_prefix, "random", "R", false, "random query name")
+	queryCmd.Flags().StringVarP(&query_port, "port", "p", "53", "query target port")
+	queryCmd.Flags().StringVarP(&query_name, "name", "d", "example.com", "query name in DNS requests")
+	queryCmd.Flags().Uint16VarP(&query_type, "type", "t", 1, "target record type")
+	queryCmd.Flags().Uint16VarP(&query_class, "class", "c", 1, "target record class")
+	queryCmd.Flags().IntVarP(&query_rate, "rate", "r", 10, "request rate (packets per second)")
+	queryCmd.Flags().IntVarP(&query_packets, "packets", "n", 100, "total request number")
+	rootCmd.AddCommand(queryCmd)
+}
diff --git a/dtool b/dtool
index 3f38d77..f6479fc 100755
Binary files a/dtool and b/dtool differ
diff --git a/prober/cache_prober.go b/prober/cache_prober.go
index 94adeb0..7b7890d 100644
--- a/prober/cache_prober.go
+++ b/prober/cache_prober.go
@@ -27,7 +27,7 @@ func RecursiveCacheProbe(ip string, sld string) CacheStruct {
 		}
 		subdomain := strings.Join([]string{strings.Replace(ip, ".", "-", -1), "fwd", strconv.Itoa(i), time_now}, "-")
 		domain := dns.Fqdn(subdomain + "." + sld)
-		res, err := utils.SendQuery(ip, domain)
+		res, err := utils.SendAQuery(ip, domain)
 		if err != nil {
 			//fmt.Printf("Error sending query: %s\n", err)
 			stop += 1
diff --git a/prober/rdns_prober.go b/prober/rdns_prober.go
index 4227b6a..cc36233 100644
--- a/prober/rdns_prober.go
+++ b/prober/rdns_prober.go
@@ -26,7 +26,7 @@ func active_probe(n int, addr string) RecursiveStruct {
 	for i := 0; i < n; i++ {
 		subdomain := strings.Join([]string{strings.Replace(target_ip, ".", "-", -1), "echo", strconv.Itoa(i), timestamp}, "-")
 		domain := dns.Fqdn(subdomain + ".echodns.xyz")
-		res, err := utils.SendQuery(addr, domain)
+		res, err := utils.SendAQuery(addr, domain)
 		if err != nil {
 			stop += 1
 			continue
diff --git a/utils/dns_utils.go b/utils/dns_utils.go
index 641968a..d89926e 100644
--- a/utils/dns_utils.go
+++ b/utils/dns_utils.go
@@ -75,6 +75,10 @@ func QueryMaker(query QueryStruct) *dns.Msg {
 	return msg
 }
 
+func ParseRcode(msg *dns.Msg) int {
+	return msg.MsgHdr.Rcode
+}
+
 func ParseAResponse(msg *dns.Msg) (string, error) {
 	var ip_str string
 	if len(msg.Answer) == 1 {
@@ -134,7 +138,22 @@ func ParseTXTResponse(msg *dns.Msg) (string, error) {
 	return txt_string, nil
 }
 
-func SendQuery(ip string, domain string) (*dns.Msg, error) {
+func SendQuery(ip, domain, port string, qtype, qclass uint16) (*dns.Msg, error) {
+	addr := ip + ":" + port
+	query := new(QueryStruct)
+	query.Qname = domain
+	query.RD = true
+	query.Qtype = qtype
+	query.Qclass = uint16(qclass)
+	query.Id = dns.Id()
+	m := QueryMaker(*query)
+
+	res, err := dns.Exchange(m, addr)
+
+	return res, err
+}
+
+func SendAQuery(ip string, domain string) (*dns.Msg, error) {
 	addr := ip + ":53"
 	query := new(QueryStruct)
 	query.Qname = domain