diff --git a/dhcpd/check_other_dhcp.go b/dhcpd/check_other_dhcp.go
index 6c6f353b..e7c1c89c 100644
--- a/dhcpd/check_other_dhcp.go
+++ b/dhcpd/check_other_dhcp.go
@@ -2,16 +2,14 @@ package dhcpd
 
 import (
 	"bytes"
-	"crypto/rand"
-	"encoding/binary"
 	"fmt"
-	"math"
 	"net"
 	"os"
 	"time"
 
 	"github.com/AdguardTeam/golibs/log"
-	"github.com/krolaw/dhcp4"
+	"github.com/insomniacslk/dhcp/dhcpv4"
+	"github.com/insomniacslk/dhcp/iana"
 	"golang.org/x/net/ipv4"
 )
 
@@ -34,51 +32,17 @@ func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
 	src := net.JoinHostPort(srcIP.String(), "68")
 	dst := "255.255.255.255:67"
 
-	// form a DHCP request packet, try to emulate existing client as much as possible
-	xID := make([]byte, 4)
-	n, err := rand.Read(xID)
-	if n != 4 && err == nil {
-		err = fmt.Errorf("Generated less than 4 bytes")
-	}
-	if err != nil {
-		return false, wrapErrPrint(err, "Couldn't generate random bytes")
-	}
-	hostname, err := os.Hostname()
-	if err != nil {
-		return false, wrapErrPrint(err, "Couldn't get hostname")
-	}
-	requestList := []byte{
-		byte(dhcp4.OptionSubnetMask),
-		byte(dhcp4.OptionClasslessRouteFormat),
-		byte(dhcp4.OptionRouter),
-		byte(dhcp4.OptionDomainNameServer),
-		byte(dhcp4.OptionDomainName),
-		byte(dhcp4.OptionDomainSearch),
-		252, // private/proxy autodiscovery
-		95,  // LDAP
-		byte(dhcp4.OptionNetBIOSOverTCPIPNameServer),
-		byte(dhcp4.OptionNetBIOSOverTCPIPNodeType),
-	}
-	maxUDPsizeRaw := make([]byte, 2)
-	binary.BigEndian.PutUint16(maxUDPsizeRaw, 1500)
-	leaseTimeRaw := make([]byte, 4)
-	leaseTime := uint32(math.RoundToEven((time.Hour * 24 * 90).Seconds()))
-	binary.BigEndian.PutUint32(leaseTimeRaw, leaseTime)
-	options := []dhcp4.Option{
-		{Code: dhcp4.OptionParameterRequestList, Value: requestList},
-		{Code: dhcp4.OptionMaximumDHCPMessageSize, Value: maxUDPsizeRaw},
-		{Code: dhcp4.OptionClientIdentifier, Value: append([]byte{0x01}, iface.HardwareAddr...)},
-		{Code: dhcp4.OptionIPAddressLeaseTime, Value: leaseTimeRaw},
-		{Code: dhcp4.OptionHostName, Value: []byte(hostname)},
-	}
-	packet := dhcp4.RequestPacket(dhcp4.Discover, iface.HardwareAddr, nil, xID, false, options)
+	hostname, _ := os.Hostname()
+
+	req, err := dhcpv4.NewDiscovery(iface.HardwareAddr)
+	req.Options.Update(dhcpv4.OptClientIdentifier(iface.HardwareAddr))
+	req.Options.Update(dhcpv4.OptHostName(hostname))
 
 	// resolve 0.0.0.0:68
 	udpAddr, err := net.ResolveUDPAddr("udp4", src)
 	if err != nil {
 		return false, wrapErrPrint(err, "Couldn't resolve UDP address %s", src)
 	}
-	// spew.Dump(udpAddr, err)
 
 	if !udpAddr.IP.To4().Equal(srcIP) {
 		return false, wrapErrPrint(err, "Resolved UDP address is not %s", src)
@@ -102,7 +66,7 @@ func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
 
 	// send to 255.255.255.255:67
 	cm := ipv4.ControlMessage{}
-	_, err = c.WriteTo(packet, &cm, dstAddr)
+	_, err = c.WriteTo(req.ToBytes(), &cm, dstAddr)
 	if err != nil {
 		return false, wrapErrPrint(err, "Couldn't send a packet to %s", dst)
 	}
@@ -113,7 +77,7 @@ func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
 		// TODO: replicate dhclient's behaviour of retrying several times with progressively bigger timeouts
 		b := make([]byte, 1500)
 		_ = c.SetReadDeadline(time.Now().Add(defaultDiscoverTime))
-		n, _, _, err = c.ReadFrom(b)
+		n, _, _, err := c.ReadFrom(b)
 		if isTimeout(err) {
 			// timed out -- no DHCP servers
 			return false, nil
@@ -121,27 +85,24 @@ func CheckIfOtherDHCPServersPresent(ifaceName string) (bool, error) {
 		if err != nil {
 			return false, wrapErrPrint(err, "Couldn't receive packet")
 		}
-		// spew.Dump(n, fromAddr, err, b)
 
 		log.Tracef("Received packet (%v bytes)", n)
 
-		if n < 240 {
-			// packet too small for dhcp
+		response, err := dhcpv4.FromBytes(b[:n])
+		if err != nil {
+			log.Debug("DHCPv4: dhcpv4.FromBytes: %s", err)
 			continue
 		}
 
-		response := dhcp4.Packet(b[:n])
-		if response.OpCode() != dhcp4.BootReply ||
-			response.HType() != 1 /*Ethernet*/ ||
-			response.HLen() > 16 ||
-			!bytes.Equal(response.CHAddr(), iface.HardwareAddr) ||
-			!bytes.Equal(response.XId(), xID) {
-			continue
-		}
+		log.Debug("DHCPv4: received message from server: %s", response.Summary())
 
-		parsedOptions := response.ParseOptions()
-		if t := parsedOptions[dhcp4.OptionDHCPMessageType]; len(t) != 1 {
-			continue //packet without DHCP message type
+		if !(response.OpCode == dhcpv4.OpcodeBootReply &&
+			response.HWType == iana.HWTypeEthernet &&
+			bytes.Equal(response.ClientHWAddr, iface.HardwareAddr) &&
+			bytes.Equal(response.TransactionID[:], req.TransactionID[:]) &&
+			response.Options.Has(dhcpv4.OptionDHCPMessageType)) {
+			log.Debug("DHCPv4: received message from server doesn't match our request")
+			continue
 		}
 
 		log.Tracef("The packet is from an active DHCP server")
diff --git a/dhcpd/dhcpd.go b/dhcpd/dhcpd.go
index 38b3b3d3..ba3538c9 100644
--- a/dhcpd/dhcpd.go
+++ b/dhcpd/dhcpd.go
@@ -15,9 +15,8 @@ const leaseExpireStatic = 1
 var webHandlersRegistered = false
 
 // Lease contains the necessary information about a DHCP lease
-// field ordering is important -- yaml fields will mirror ordering from here
 type Lease struct {
-	HWAddr   net.HardwareAddr `json:"mac" yaml:"hwaddr"`
+	HWAddr   net.HardwareAddr `json:"mac"`
 	IP       net.IP           `json:"ip"`
 	Hostname string           `json:"hostname"`
 
@@ -29,17 +28,17 @@ type Lease struct {
 // ServerConfig - DHCP server configuration
 // field ordering is important -- yaml fields will mirror ordering from here
 type ServerConfig struct {
-	Conf4 V4ServerConf `json:"-" yaml:"dhcpv4"`
-	Conf6 V6ServerConf `json:"-" yaml:"dhcpv6"`
+	Conf4 V4ServerConf `yaml:"dhcpv4"`
+	Conf6 V6ServerConf `yaml:"dhcpv6"`
 
-	WorkDir    string `json:"-" yaml:"-"`
-	DBFilePath string `json:"-" yaml:"-"` // path to DB file
+	WorkDir    string `yaml:"-"`
+	DBFilePath string `yaml:"-"` // path to DB file
 
 	// Called when the configuration is changed by HTTP request
-	ConfigModified func() `json:"-" yaml:"-"`
+	ConfigModified func() `yaml:"-"`
 
 	// Register an HTTP handler
-	HTTPRegister func(string, string, func(http.ResponseWriter, *http.Request)) `json:"-" yaml:"-"`
+	HTTPRegister func(string, string, func(http.ResponseWriter, *http.Request)) `yaml:"-"`
 }
 
 type onLeaseChangedT func(flags int)
diff --git a/go.mod b/go.mod
index bf7a29fc..faab69fa 100644
--- a/go.mod
+++ b/go.mod
@@ -13,7 +13,6 @@ require (
 	github.com/insomniacslk/dhcp v0.0.0-20200420235442-ed3125c2efe7
 	github.com/joomcode/errorx v1.0.1
 	github.com/kardianos/service v1.0.0
-	github.com/krolaw/dhcp4 v0.0.0-20180925202202-7cead472c414
 	github.com/mdlayher/ethernet v0.0.0-20190606142754-0394541c37b7 // indirect
 	github.com/mdlayher/raw v0.0.0-20191009151244-50f2db8cc065 // indirect
 	github.com/miekg/dns v1.1.29
diff --git a/go.sum b/go.sum
index 9b393a7e..404a35e5 100644
--- a/go.sum
+++ b/go.sum
@@ -74,8 +74,6 @@ github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
-github.com/krolaw/dhcp4 v0.0.0-20180925202202-7cead472c414 h1:6wnYc2S/lVM7BvR32BM74ph7bPgqMztWopMYKgVyEho=
-github.com/krolaw/dhcp4 v0.0.0-20180925202202-7cead472c414/go.mod h1:0AqAH3ZogsCrvrtUpvc6EtVKbc3w6xwZhkvGLuqyi3o=
 github.com/magiconair/properties v1.8.0/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
 github.com/mdlayher/ethernet v0.0.0-20190606142754-0394541c37b7 h1:lez6TS6aAau+8wXUP3G9I3TGlmPFEq2CTxBaRqY6AGE=
 github.com/mdlayher/ethernet v0.0.0-20190606142754-0394541c37b7/go.mod h1:U6ZQobyTjI/tJyq2HG+i/dfSoFUt8/aZCM+GKtmFk/Y=