diff --git a/ciscoasa/interfaces.go b/ciscoasa/interfaces.go
index 33b3055..f803a0a 100644
--- a/ciscoasa/interfaces.go
+++ b/ciscoasa/interfaces.go
@@ -26,17 +26,41 @@ type interfaceService struct {
 	*Client
 }
 
-// IPAddress represents an IPv4 address.
+// SlaTracking represents an SlaTracking Settings.
+type SlaTracking struct {
+	SlaId                   int    `json:"slaId"`
+	TrackedIP               string `json:"trackedIP"`
+	FrequencyInSeconds      int    `json:"frequencyInSeconds"`
+	DataSizeInBytes         int    `json:"dataSizeInBytes"`
+	ThresholdInMilliseconds int    `json:"thresholdInMilliseconds"`
+	ToS                     int    `json:"ToS"`
+	TimeoutInMilliseconds   int    `json:"timeoutInMilliseconds"`
+	NumPackets              int    `json:"numPackets"`
+}
+
+// DhcpClient represents an DHCP Settings.
+type DhcpClient struct {
+	SetDefaultRoute     bool         `json:"setDefaultRoute"`
+	Metric              int          `json:"metric"`
+	PrimaryTrackId      int          `json:"primaryTrackId"`
+	TrackingEnabled     bool         `json:"trackingEnabled"`
+	SlaTrackingSettings *SlaTracking `json:"slaTrackingSettings"`
+}
+
+// Address represents a static IPv4/IPv6 address settings.
+type Address struct {
+	Kind  string `json:"kind"`
+	Value string `json:"value"`
+}
+
+// IPAddress represents an IP address settings.
 type IPAddress struct {
-	IP struct {
-		Kind  string `json:"kind"`
-		Value string `json:"value"`
-	} `json:"ip"`
-	NetMask struct {
-		Kind  string `json:"kind"`
-		Value string `json:"value"`
-	} `json:"netMask"`
-	Kind string `json:"kind"`
+	IP                 *Address    `json:"ip,omitempty"`
+	NetMask            *Address    `json:"netMask,omitempty"`
+	Kind               string      `json:"kind"`
+	DhcpOptionUsingMac bool        `json:"dhcpOptionUsingMac,omitempty"`
+	DhcpBroadcast      bool        `json:"dhcpBroadcast,omitempty"`
+	DhcpClient         *DhcpClient `json:"dhcpClient,omitempty"`
 }
 
 // UnmarshalJSON implements json.Unmarshaler interface.
@@ -56,23 +80,44 @@ func (ip *IPAddress) String() string {
 	return ip.IP.Value + "/" + bitsize
 }
 
+// nDiscoveryPrefix represents an nDiscoveryPrefix list.
+type NDiscoveryPrefix struct {
+	OffLink           bool   `json:"offLink"`
+	NoAdvertise       bool   `json:"noAdvertise"`
+	PreferredLifetime int    `json:"preferredLifetime"`
+	ValidLifetime     int    `json:"validLifetime"`
+	HasDuration       bool   `json:"hasDuration"`
+	DefaultPrefix     bool   `json:"defaultPrefix"`
+	Kind              string `json:"kind"`
+}
+
+// Ipv6Address represents an Ipv6Address.
+type Ipv6Address struct {
+	PrefixLength int      `json:"prefixLength,omitempty"`
+	Standby      *Address `json:"standby,omitempty"`
+	Address      *Address `json:"address,omitempty"`
+	// IsEUI64      bool     `json:"isEUI64"`
+	Kind string `json:"kind"`
+}
+
 // IPv6Info represents an IPv6 address.
 type IPv6Info struct {
-	Enabled                  bool     `json:"enabled"`
-	AutoConfig               bool     `json:"autoConfig"`
-	EnforceEUI64             bool     `json:"enforceEUI64"`
-	ManagedAddressConfig     bool     `json:"managedAddressConfig"`
-	NsInterval               int      `json:"nsInterval"`
-	DadAttempts              int      `json:"dadAttempts"`
-	NDiscoveryPrefixList     []string `json:"nDiscoveryPrefixList"`
-	OtherStatefulConfig      bool     `json:"otherStatefulConfig"`
-	RouterAdvertInterval     int      `json:"routerAdvertInterval"`
-	RouterAdvertIntervalUnit string   `json:"routerAdvertIntervalUnit"`
-	RouterAdvertLifetime     int      `json:"routerAdvertLifetime"`
-	SuppressRouterAdvert     bool     `json:"suppressRouterAdvert"`
-	ReachableTime            int      `json:"reachableTime"`
-	Ipv6Addresses            []string `json:"ipv6Addresses"`
-	Kind                     string   `json:"kind"`
+	Enabled                  bool                `json:"enabled"`
+	AutoConfig               bool                `json:"autoConfig"`
+	EnforceEUI64             bool                `json:"enforceEUI64"`
+	ManagedAddressConfig     bool                `json:"managedAddressConfig"`
+	NsInterval               int                 `json:"nsInterval"`
+	DadAttempts              int                 `json:"dadAttempts"`
+	NDiscoveryPrefixList     []*NDiscoveryPrefix `json:"nDiscoveryPrefixList,omitempty"`
+	OtherStatefulConfig      bool                `json:"otherStatefulConfig"`
+	RouterAdvertInterval     int                 `json:"routerAdvertInterval"`
+	RouterAdvertIntervalUnit string              `json:"routerAdvertIntervalUnit"`
+	RouterAdvertLifetime     int                 `json:"routerAdvertLifetime"`
+	SuppressRouterAdvert     bool                `json:"suppressRouterAdvert"`
+	ReachableTime            int                 `json:"reachableTime"`
+	LinkLocalAddress         *Ipv6Address        `json:"linkLocalAddress,omitempty"`
+	Ipv6Addresses            []*Ipv6Address      `json:"ipv6Addresses,omitempty"`
+	Kind                     string              `json:"kind"`
 }
 
 // UnmarshalJSON implements json.Unmarshaler interface.
diff --git a/ciscoasa/interfaces_physical.go b/ciscoasa/interfaces_physical.go
index 2fd74bd..88ef3bf 100644
--- a/ciscoasa/interfaces_physical.go
+++ b/ciscoasa/interfaces_physical.go
@@ -32,7 +32,7 @@ type PhysicalInterface struct {
 	InterfaceDesc     string     `json:"interfaceDesc"`
 	ChannelGroupID    string     `json:"channelGroupID"`
 	ChannelGroupMode  string     `json:"channelGroupMode"`
-	Duplex            string     `json:"duplex"`
+	Duplex            string     `json:"duplex,omitempty"`
 	FlowcontrolOn     bool       `json:"flowcontrolOn"`
 	FlowcontrolHigh   int        `json:"flowcontrolHigh"`
 	FlowcontrolLow    int        `json:"flowcontrolLow"`
@@ -47,12 +47,12 @@ type PhysicalInterface struct {
 	Name              string     `json:"name"`
 	SecurityLevel     int        `json:"securityLevel"`
 	Shutdown          bool       `json:"shutdown"`
-	Speed             string     `json:"speed"`
-	IPAddress         *IPAddress `json:"ipAddress"`
-	Ipv6Info          *IPv6Info  `json:"ipv6Info"`
+	Speed             string     `json:"speed,omitempty"`
+	IPAddress         *IPAddress `json:"ipAddress,omitempty"`
+	Ipv6Info          *IPv6Info  `json:"ipv6Info,omitempty"`
 	Kind              string     `json:"kind"`
-	ObjectID          string     `json:"objectId"`
-	SelfLink          string     `json:"selfLink"`
+	ObjectID          string     `json:"objectId,omitempty"`
+	SelfLink          string     `json:"selfLink,omitempty"`
 }
 
 // ListPhysicalInterfaces returns a collection of interfaces.
@@ -88,3 +88,144 @@ func (s *interfaceService) ListPhysicalInterfaces() (*PhysicalInterfaceCollectio
 
 	return result, nil
 }
+
+// UpdatePhysicalInterface updates a physical interface
+// as there is no way of creating a physical interface.
+func (s *interfaceService) UpdatePhysicalInterface(
+	activeMacAddress string,
+	forwardTrafficCX bool,
+	forwardTrafficSFR bool,
+	hardwareID string,
+	interfaceDesc string,
+	ipAddress *IPAddress,
+	ipv6Info *IPv6Info,
+	kind string,
+	managementOnly bool,
+	mtu int,
+	name string,
+	objectID string,
+	securityLevel int,
+	shutdown bool,
+	standByMacAddress string,
+) (string, error) {
+	u := fmt.Sprintf("/api/interfaces/physical/%s", objectID)
+
+	duplex := "auto"
+	speed := "auto"
+	if kind == "object#TenGigInterface" {
+		duplex = ""
+		speed = ""
+	}
+
+	r := &PhysicalInterface{
+		ActiveMacAddress:  activeMacAddress,
+		ChannelGroupID:    "",
+		ChannelGroupMode:  "active",
+		Duplex:            duplex,
+		FlowcontrolHigh:   -1,
+		FlowcontrolLow:    -1,
+		FlowcontrolOn:     false,
+		FlowcontrolPeriod: -1,
+		ForwardTrafficCX:  forwardTrafficCX,
+		ForwardTrafficSFR: forwardTrafficSFR,
+		HardwareID:        hardwareID,
+		InterfaceDesc:     interfaceDesc,
+		IPAddress:         ipAddress,
+		Ipv6Info:          ipv6Info,
+		Kind:              kind,
+		LacpPriority:      -1,
+		ManagementOnly:    managementOnly,
+		Mtu:               mtu,
+		Name:              name,
+		ObjectID:          objectID,
+		SecurityLevel:     securityLevel,
+		Shutdown:          shutdown,
+		Speed:             speed,
+		StandByMacAddress: standByMacAddress,
+	}
+
+	req, err := s.newRequest("PUT", u, r)
+	if err != nil {
+		return "", err
+	}
+
+	resp, err := s.do(req, nil)
+	if err != nil {
+		return "", err
+	}
+
+	return idFromResponse(resp)
+}
+
+// GetPhysicalInterface retrieves a physical interface.
+func (s *interfaceService) GetPhysicalInterface(objectID string) (*PhysicalInterface, error) {
+	u := fmt.Sprintf("/api/interfaces/physical/%s", objectID)
+
+	req, err := s.newRequest("GET", u, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	r := &PhysicalInterface{}
+	_, err = s.do(req, r)
+
+	return r, err
+}
+
+// DeletePhysicalInterface sets values to defaults
+// as there is no way of deletion a physical interface.
+func (s *interfaceService) DeletePhysicalInterface(
+	hardwareID string,
+	kind string,
+	objectID string,
+) error {
+	u := fmt.Sprintf("/api/interfaces/physical/%s", objectID)
+
+	duplex := "auto"
+	speed := "auto"
+	if kind == "object#TenGigInterface" {
+		duplex = ""
+		speed = ""
+	}
+
+	r := &PhysicalInterface{
+		ActiveMacAddress:  "",
+		ChannelGroupID:    "",
+		ChannelGroupMode:  "active",
+		Duplex:            duplex,
+		FlowcontrolHigh:   -1,
+		FlowcontrolLow:    -1,
+		FlowcontrolOn:     false,
+		FlowcontrolPeriod: -1,
+		ForwardTrafficCX:  false,
+		ForwardTrafficSFR: false,
+		HardwareID:        hardwareID,
+		InterfaceDesc:     "",
+		IPAddress:         nil,
+		Ipv6Info:          nil,
+		Kind:              kind,
+		LacpPriority:      -1,
+		ManagementOnly:    false,
+		Mtu:               1500,
+		Name:              "",
+		SecurityLevel:     -1,
+		Shutdown:          false,
+		Speed:             speed,
+		StandByMacAddress: "",
+	}
+
+	req, err := s.newRequest("PUT", u, r)
+	if err != nil {
+		return err
+	}
+
+	resp, err := s.do(req, nil)
+	if err != nil {
+		return err
+	}
+
+	err = checkResponse(resp)
+
+	return err
+
+}
diff --git a/ciscoasa/interfaces_vlan.go b/ciscoasa/interfaces_vlan.go
index 105e1df..1446f17 100644
--- a/ciscoasa/interfaces_vlan.go
+++ b/ciscoasa/interfaces_vlan.go
@@ -40,11 +40,11 @@ type VlanInterface struct {
 	SecurityLevel     int        `json:"securityLevel"`
 	Shutdown          bool       `json:"shutdown"`
 	VlanID            int        `json:"vlanID"`
-	IPAddress         *IPAddress `json:"ipAddress"`
-	Ipv6Info          *IPv6Info  `json:"ipv6Info"`
+	IPAddress         *IPAddress `json:"ipAddress,omitempty"`
+	Ipv6Info          *IPv6Info  `json:"ipv6Info,omitempty"`
 	Kind              string     `json:"kind"`
-	ObjectID          string     `json:"objectId"`
-	SelfLink          string     `json:"selfLink"`
+	ObjectID          string     `json:"objectId,omitempty"`
+	SelfLink          string     `json:"selfLink,omitempty"`
 }
 
 // ListVlanInterfaces returns a collection of interfaces.
@@ -80,3 +80,138 @@ func (s *interfaceService) ListVlanInterfaces() (*VlanInterfaceCollection, error
 
 	return result, nil
 }
+
+// CreateVlanInterface creates a vlan interface.
+func (s *interfaceService) CreateVlanInterface(
+	activeMacAddress string,
+	forwardTrafficCX bool,
+	forwardTrafficSFR bool,
+	hardwareID string,
+	interfaceDesc string,
+	ipAddress *IPAddress,
+	ipv6Info *IPv6Info,
+	kind string,
+	managementOnly bool,
+	mtu int,
+	name string,
+	securityLevel int,
+	shutdown bool,
+	standByMacAddress string,
+	vlanId int,
+) (string, error) {
+	u := "/api/interfaces/vlan/"
+
+	r := &VlanInterface{
+		ActiveMacAddress:  activeMacAddress,
+		ForwardTrafficCX:  forwardTrafficCX,
+		ForwardTrafficSFR: forwardTrafficSFR,
+		HardwareID:        hardwareID,
+		InterfaceDesc:     interfaceDesc,
+		IPAddress:         ipAddress,
+		Ipv6Info:          ipv6Info,
+		Kind:              kind,
+		ManagementOnly:    managementOnly,
+		Mtu:               mtu,
+		Name:              name,
+		SecurityLevel:     securityLevel,
+		Shutdown:          shutdown,
+		StandByMacAddress: standByMacAddress,
+		VlanID:            vlanId,
+	}
+
+	req, err := s.newRequest("POST", u, r)
+	if err != nil {
+		return "", err
+	}
+
+	resp, err := s.do(req, nil)
+	if err != nil {
+		return "", err
+	}
+
+	return idFromResponse(resp)
+}
+
+// UpdateVlanInterface updates a vlan interface.
+func (s *interfaceService) UpdateVlanInterface(
+	activeMacAddress string,
+	forwardTrafficCX bool,
+	forwardTrafficSFR bool,
+	hardwareID string,
+	interfaceDesc string,
+	ipAddress *IPAddress,
+	ipv6Info *IPv6Info,
+	kind string,
+	managementOnly bool,
+	mtu int,
+	name string,
+	objectID string,
+	securityLevel int,
+	shutdown bool,
+	standByMacAddress string,
+	vlanId int,
+) error {
+	u := fmt.Sprintf("/api/interfaces/vlan/%s", objectID)
+
+	r := &VlanInterface{
+		ActiveMacAddress:  activeMacAddress,
+		ForwardTrafficCX:  forwardTrafficCX,
+		ForwardTrafficSFR: forwardTrafficSFR,
+		HardwareID:        hardwareID,
+		InterfaceDesc:     interfaceDesc,
+		IPAddress:         ipAddress,
+		Ipv6Info:          ipv6Info,
+		Kind:              kind,
+		ManagementOnly:    managementOnly,
+		Mtu:               mtu,
+		Name:              name,
+		ObjectID:          objectID,
+		SecurityLevel:     securityLevel,
+		Shutdown:          shutdown,
+		StandByMacAddress: standByMacAddress,
+		VlanID:            vlanId,
+	}
+
+	req, err := s.newRequest("PUT", u, r)
+	if err != nil {
+		return err
+	}
+
+	resp, err := s.do(req, nil)
+	if err != nil {
+		return err
+	}
+
+	err = checkResponse(resp)
+
+	return err
+}
+
+// GetVlanInterface retrieves a vlan interface.
+func (s *interfaceService) GetVlanInterface(objectID string) (*VlanInterface, error) {
+	u := fmt.Sprintf("/api/interfaces/vlan/%s", objectID)
+
+	req, err := s.newRequest("GET", u, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	r := &VlanInterface{}
+	_, err = s.do(req, r)
+
+	return r, err
+}
+
+// DeleteVlanInterface deletes a vlan interface.
+func (s *interfaceService) DeleteVlanInterface(objectID string) error {
+	u := fmt.Sprintf("/api/interfaces/vlan/%s", objectID)
+
+	req, err := s.newRequest("DELETE", u, nil)
+	if err != nil {
+		return err
+	}
+
+	_, err = s.do(req, nil)
+
+	return err
+}
diff --git a/go.mod b/go.mod
index 605c199..983ae59 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,3 @@
 module github.com/xanzy/go-ciscoasa
 
-go 1.12
+go 1.16