diff --git a/README.md b/README.md
index 7937438..c8edbd6 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@
 ### UPF
 
 ```golang
-upNode := NewPFCPEntityUP(UPFADDR)
+upNode := NewPFCPEntityUP(UPF_NODE_ID, UPF_IP_ADDR) // node id can be an IP Address or a FQDN
 upNode.Start()
 // Access list of associations
 associations := upNode.GetPFCPAssociations()
@@ -21,7 +21,7 @@ sessions := upNode.GetPFCPSessions()
 ### SMF
 
 ```golang
-cpNode := NewPFCPEntityCP(SMFADDR)
+cpNode := NewPFCPEntityCP(SMF_NODE_ID, SMF_IP_ADDR) // node id can be an IP Address or a FQDN
 cpNode.Start()
 association, _ := cpNode.NewEstablishedPFCPAssociation(ie.NewNodeIDHeuristic(UPFADDR))
 session, _ := a.CreateSession(pdrs, fars)
diff --git a/pfcp/entity.go b/pfcp/entity.go
index bc9a020..760b661 100644
--- a/pfcp/entity.go
+++ b/pfcp/entity.go
@@ -20,6 +20,7 @@ import (
 
 type PFCPEntity struct {
 	nodeID            *ie.IE
+	listenAddr        string
 	recoveryTimeStamp *ie.IE
 	handlers          map[pfcputil.MessageType]PFCPMessageHandler
 	conn              *net.UDPConn
@@ -73,9 +74,10 @@ func newDefaultPFCPEntityHandlers() map[pfcputil.MessageType]PFCPMessageHandler
 	return m
 }
 
-func NewPFCPEntity(nodeID string, kind string, options EntityOptions) PFCPEntity {
+func NewPFCPEntity(nodeID string, listenAddr string, kind string, options EntityOptions) PFCPEntity {
 	return PFCPEntity{
 		nodeID:            ie.NewNodeIDHeuristic(nodeID),
+		listenAddr:        listenAddr,
 		recoveryTimeStamp: nil,
 		handlers:          newDefaultPFCPEntityHandlers(),
 		conn:              nil,
@@ -89,11 +91,8 @@ func NewPFCPEntity(nodeID string, kind string, options EntityOptions) PFCPEntity
 
 func (e *PFCPEntity) listen() error {
 	e.recoveryTimeStamp = ie.NewRecoveryTimeStamp(time.Now())
-	// TODO: if NodeID is a FQDN, we can expose multiple ip addresses
-	ipAddr, err := e.NodeID().NodeID()
-	if err != nil {
-		return err
-	}
+	// TODO: listen on multiple ip addresses (ipv4 + ipv6)
+	ipAddr := e.listenAddr
 	udpAddr := pfcputil.CreateUDPAddr(ipAddr, pfcputil.PFCP_PORT)
 	laddr, err := net.ResolveUDPAddr("udp", udpAddr)
 	if err != nil {
diff --git a/pfcp/entity_cp.go b/pfcp/entity_cp.go
index 77bddc2..204d44e 100644
--- a/pfcp/entity_cp.go
+++ b/pfcp/entity_cp.go
@@ -9,10 +9,10 @@ type PFCPEntityCP struct {
 	PFCPEntity
 }
 
-func NewPFCPEntityCP(nodeID string) *PFCPEntityCP {
-	return NewPFCPEntityCPWithOptions(nodeID, EntityOptions{})
+func NewPFCPEntityCP(nodeID string, listenAddr string) *PFCPEntityCP {
+	return NewPFCPEntityCPWithOptions(nodeID, listenAddr, EntityOptions{})
 }
 
-func NewPFCPEntityCPWithOptions(nodeID string, options EntityOptions) *PFCPEntityCP {
-	return &PFCPEntityCP{PFCPEntity: NewPFCPEntity(nodeID, "CP", options)}
+func NewPFCPEntityCPWithOptions(nodeID string, listenAddr string, options EntityOptions) *PFCPEntityCP {
+	return &PFCPEntityCP{PFCPEntity: NewPFCPEntity(nodeID, listenAddr, "CP", options)}
 }
diff --git a/pfcp/entity_up.go b/pfcp/entity_up.go
index 1d2ce13..f05b03f 100644
--- a/pfcp/entity_up.go
+++ b/pfcp/entity_up.go
@@ -15,12 +15,12 @@ type PFCPEntityUP struct {
 	PFCPEntity
 }
 
-func NewPFCPEntityUP(nodeID string) *PFCPEntityUP {
-	return NewPFCPEntityUPWithOptions(nodeID, EntityOptions{})
+func NewPFCPEntityUP(nodeID string, listenAddr string) *PFCPEntityUP {
+	return NewPFCPEntityUPWithOptions(nodeID, listenAddr, EntityOptions{})
 }
 
-func NewPFCPEntityUPWithOptions(nodeID string, options EntityOptions) *PFCPEntityUP {
-	e := PFCPEntityUP{PFCPEntity: NewPFCPEntity(nodeID, "UP", options)}
+func NewPFCPEntityUPWithOptions(nodeID string, listenAddr string, options EntityOptions) *PFCPEntityUP {
+	e := PFCPEntityUP{PFCPEntity: NewPFCPEntity(nodeID, listenAddr, "UP", options)}
 	err := e.initDefaultHandlers()
 	if err != nil {
 		log.Println(err)