diff --git a/discovery/host.go b/discovery/host.go
index d5d2968..abb1fc0 100644
--- a/discovery/host.go
+++ b/discovery/host.go
@@ -1,12 +1,12 @@
 package discovery
 
 import (
-	"bytes"
 	"fmt"
 	"net"
 	"time"
 
 	"git.loafle.net/commons_go/logging"
+	"git.loafle.net/commons_go/util/net/cidr"
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
 
@@ -21,6 +21,16 @@ func scanHost(zone *model.Zone, dh *model.DiscoveryHost, resultChan chan interfa
 		// doneChan <- struct{}{}
 		return
 	}
+	cr, err := cidr.NewCIDRRanger(zone.Network)
+	if nil != err {
+		errChan <- err
+		return
+	}
+	hostRanges, err := getTargetHostRange(dh, cr)
+	if nil != err {
+		errChan <- err
+		return
+	}
 
 	arpChan := ps.OpenARP()
 	defer func() {
@@ -40,21 +50,26 @@ func scanHost(zone *model.Zone, dh *model.DiscoveryHost, resultChan chan interfa
 					logging.Logger().Debug(fmt.Sprintf("Discovery: arp channel is closed"))
 					return
 				}
-				if h := handlePacketARP(zone, hosts, packet); nil != h {
+				if h := handlePacketARP(zone, cr, hosts, packet); nil != h {
 					logging.Logger().Debug(fmt.Sprintf("Discovery: Host[%v] is founded", h))
 				}
 			}
 		}
 	}()
 
+	if err := sendARP(ps, zone, hostRanges); nil != err {
+		errChan <- err
+		return
+	}
+
 	time.Sleep(30 * time.Second)
 }
 
-func handlePacketARP(zone *model.Zone, hosts map[string]*model.Host, packet *layers.ARP) *model.Host {
+func handlePacketARP(zone *model.Zone, cr cidr.CIDRRanger, hosts map[string]*model.Host, packet *layers.ARP) *model.Host {
 	// logging.Logger().Debug(fmt.Sprintf("Discovery: arp packet %v", packet))
 
 	ip := net.IP(packet.SourceProtAddress)
-	if _, ok := hosts[ip.String()]; ok {
+	if _, ok := hosts[ip.String()]; ok || !cr.Contains(ip) {
 		return nil
 	}
 	h := &model.Host{}
@@ -67,103 +82,47 @@ func handlePacketARP(zone *model.Zone, hosts map[string]*model.Host, packet *lay
 	return h
 }
 
-func sendARP(ps pcap.PCapScanner, zone *model.Zone, dh *model.DiscoveryHost) error {
+func sendARP(ps pcap.PCapScanner, zone *model.Zone, hostRanges []net.IP) error {
 	hwAddr, err := net.ParseMAC(zone.Mac)
 	if nil != err {
 		return err
 	}
 	ip := net.ParseIP(zone.IP)
-	if nil != ip {
+	if nil == ip {
 		return fmt.Errorf("Discovery: IP(%s) of zone is not valid", zone.IP)
 	}
 
-	ranges, err := getTargetHostRange(zone, dh)
-	if nil != err {
-		return err
-	}
-
 	ethPacket := makePacketEthernet(hwAddr)
 	arpPacket := makePacketARP(hwAddr, ip)
 	opts := gopacket.SerializeOptions{FixLengths: true, ComputeChecksums: true}
 	buf := gopacket.NewSerializeBuffer()
 
-	for _, targetHost := range ranges {
+	for _, targetHost := range hostRanges {
 		arpPacket.DstProtAddress = []byte(targetHost)
 		gopacket.SerializeLayers(buf, opts, ethPacket, arpPacket)
-		// if err := ps.WritePacketData(buf.Bytes()); err != nil {
-		// 	return err
-		// }
+		if err := ps.WritePacketData(buf.Bytes()); err != nil {
+			return err
+		}
 		time.Sleep(time.Microsecond * 500)
 	}
 	return nil
 }
 
-func getTargetHostRange(zone *model.Zone, dh *model.DiscoveryHost) ([]net.IP, error) {
-	nIP, nIPNet, err := net.ParseCIDR(zone.Network)
-	if nil != err {
-		return nil, fmt.Errorf("Discovery: Network(%s) of zone is not valid", zone.Network)
-	}
-
-	firstIP := net.ParseIP(dh.FirstScanRange)
-	lastIP := net.ParseIP(dh.LastScanRange)
-	if nil == firstIP || nil == lastIP {
-		return nil, fmt.Errorf("Discovery: IP Range(First:%s, Last:%s) is not valid", dh.FirstScanRange, dh.LastScanRange)
-	}
-
-	firstIP16 := firstIP.To16()
-	lastIP16 := lastIP.To16()
-	if nil == firstIP16 || nil == lastIP16 {
-		return nil, fmt.Errorf("Discovery: IP Range(First:%s, Last:%s) is not valid", dh.FirstScanRange, dh.LastScanRange)
-	}
-
-	excludeIP16s := make([]net.IP, 0)
+func getTargetHostRange(dh *model.DiscoveryHost, cr cidr.CIDRRanger) ([]net.IP, error) {
+	excludeIPs := make([]net.IP, 0)
 	for _, eHost := range dh.ExcludeHosts {
 		eIP := net.ParseIP(eHost)
 		if nil == eIP {
 			return nil, fmt.Errorf("Discovery: IP(%v) of exclude host is not valid", eHost)
 		}
-		eIP16 := eIP.To16()
-		if nil == eIP16 {
-			return nil, fmt.Errorf("Discovery: IP(%v) of exclude host is not valid", eHost)
-		}
-		excludeIP16s = append(excludeIP16s, eIP16)
+		excludeIPs = append(excludeIPs, eIP)
 	}
 
-	ranges := make([]net.IP, 0)
-
-	ip := nIP
-Loop:
-	for ip := ip.Mask(nIPNet.Mask); nIPNet.Contains(ip); inc(ip) {
-		ip16 := ip.To16()
-		if nil == ip16 {
-			return nil, fmt.Errorf("Discovery: IP(%v) converting is failed", ip)
-		}
-
-		if 0 > bytes.Compare(ip16, firstIP16) || 0 < bytes.Compare(ip16, lastIP16) {
-			continue
-		}
-
-		for _, eIP16 := range excludeIP16s {
-			if 0 == bytes.Compare(eIP16, ip16) {
-				continue Loop
-			}
-		}
-
-		ranges = append(ranges, ip)
-	}
+	ranges := cr.Range(excludeIPs)
 
 	return ranges, nil
 }
 
-func inc(ip net.IP) {
-	for j := len(ip) - 1; j >= 0; j-- {
-		ip[j]++
-		if ip[j] > 0 {
-			break
-		}
-	}
-}
-
 func makePacketEthernet(hw net.HardwareAddr) *layers.Ethernet {
 	return &layers.Ethernet{
 		SrcMAC:       hw,