diff --git a/commons/pcap/packet.go b/commons/pcap/packet.go
index 376733f..343c0e9 100644
--- a/commons/pcap/packet.go
+++ b/commons/pcap/packet.go
@@ -55,13 +55,11 @@ func handlePacketARP(ps *pCapScan, packet gopacket.Packet) {
 	ps.arpListenerChanMtx.RLock()
 	defer ps.arpListenerChanMtx.RUnlock()
 
-	if ps.arpListenerChans != nil {
-		arpLayer := packet.Layer(layers.LayerTypeARP)
-		arp := arpLayer.(*layers.ARP)
+	arpLayer := packet.Layer(layers.LayerTypeARP)
+	arp := arpLayer.(*layers.ARP)
 
-		for _, ch := range ps.arpListenerChans {
-			ch <- arp
-		}
+	for _, ch := range ps.arpListenerChans {
+		ch <- arp
 	}
 }
 
diff --git a/discovery/host.go b/discovery/host.go
index abb1fc0..cdad9c5 100644
--- a/discovery/host.go
+++ b/discovery/host.go
@@ -62,10 +62,14 @@ func scanHost(zone *model.Zone, dh *model.DiscoveryHost, resultChan chan interfa
 		return
 	}
 
-	time.Sleep(30 * time.Second)
+	time.Sleep(10 * time.Second)
 }
 
 func handlePacketARP(zone *model.Zone, cr cidr.CIDRRanger, hosts map[string]*model.Host, packet *layers.ARP) *model.Host {
+	if packet.Operation != layers.ARPReply {
+		return nil
+	}
+
 	// logging.Logger().Debug(fmt.Sprintf("Discovery: arp packet %v", packet))
 
 	ip := net.IP(packet.SourceProtAddress)
@@ -93,17 +97,18 @@ func sendARP(ps pcap.PCapScanner, zone *model.Zone, hostRanges []net.IP) error {
 	}
 
 	ethPacket := makePacketEthernet(hwAddr)
-	arpPacket := makePacketARP(hwAddr, ip)
+	arpPacket := makePacketARP(hwAddr, ip.To4())
 	opts := gopacket.SerializeOptions{FixLengths: true, ComputeChecksums: true}
 	buf := gopacket.NewSerializeBuffer()
 
 	for _, targetHost := range hostRanges {
 		arpPacket.DstProtAddress = []byte(targetHost)
-		gopacket.SerializeLayers(buf, opts, ethPacket, arpPacket)
+		// log.Printf("ARP:%v", arpPacket)
+		gopacket.SerializeLayers(buf, opts, &ethPacket, &arpPacket)
 		if err := ps.WritePacketData(buf.Bytes()); err != nil {
 			return err
 		}
-		time.Sleep(time.Microsecond * 500)
+		time.Sleep(time.Microsecond * 100)
 	}
 	return nil
 }
@@ -123,16 +128,16 @@ func getTargetHostRange(dh *model.DiscoveryHost, cr cidr.CIDRRanger) ([]net.IP,
 	return ranges, nil
 }
 
-func makePacketEthernet(hw net.HardwareAddr) *layers.Ethernet {
-	return &layers.Ethernet{
+func makePacketEthernet(hw net.HardwareAddr) layers.Ethernet {
+	return layers.Ethernet{
 		SrcMAC:       hw,
 		DstMAC:       net.HardwareAddr{0xff, 0xff, 0xff, 0xff, 0xff, 0xff},
 		EthernetType: layers.EthernetTypeARP,
 	}
 }
 
-func makePacketARP(hw net.HardwareAddr, ip net.IP) *layers.ARP {
-	return &layers.ARP{
+func makePacketARP(hw net.HardwareAddr, ip net.IP) layers.ARP {
+	return layers.ARP{
 		AddrType:          layers.LinkTypeEthernet,
 		Protocol:          layers.EthernetTypeIPv4,
 		HwAddressSize:     6,