diff --git a/Bootstrap.go b/Bootstrap.go
index 77c3ce1..7f1fc5f 100644
--- a/Bootstrap.go
+++ b/Bootstrap.go
@@ -226,12 +226,24 @@ func (peer *PeerInfo) cmdResponseBootstrapFindSelf(msg *MessageResponse, closest
 	}
 
 	for _, closePeer := range closest {
+		// Use the self-reported external port if available.
+		port := closePeer.Port
+		if closePeer.PortReportedExternal > 0 {
+			port = closePeer.PortReportedExternal
+		}
+
 		// Initiate contact. Once a response comes back, the peer is actually added to the list.
-		if contactArbitraryPeer(closePeer.PublicKey, []*net.UDPAddr{{IP: closePeer.IP, Port: int(closePeer.Port)}}) {
+		if contactArbitraryPeer(closePeer.PublicKey, []*net.UDPAddr{{IP: closePeer.IP, Port: int(port)}}) {
 			// Blacklist the target Peer ID, IP:Port for contact in the next 10 minutes.
 			// TODO
 		}
 
+		// If NAT is detected and the port is not forwarded, send a Traverse message.
+		// NAT detection is the same algorithm as peer.IsBehindNAT.
+		if closePeer.PortReportedExternal == 0 && closePeer.Port != closePeer.PortReportedInternal {
+			// TODO send traverse message
+		}
+
 	}
 }
 
diff --git a/Peer ID.go b/Peer ID.go
index 6e99aed..e8ff223 100644
--- a/Peer ID.go	
+++ b/Peer ID.go	
@@ -196,7 +196,14 @@ func record2Peer(record PeerRecord, network *Network) (peerN *PeerInfo) {
 	}
 
 	// Create temporary peer which is not added to the global list and not added to Kademlia.
-	connection := &Connection{Network: network, Address: &net.UDPAddr{IP: record.IP, Port: int(record.Port)}, Status: ConnectionActive}
+	port := record.Port
+	if record.PortReportedExternal > 0 { // Use the external port if available
+		port = record.PortReportedExternal
+	}
+
+	// TODO: Traverse message needs to be considered here
+
+	connection := &Connection{Network: network, Address: &net.UDPAddr{IP: record.IP, Port: int(port)}, Status: ConnectionActive, PortInternal: record.PortReportedInternal, PortExternal: record.PortReportedExternal}
 	return &PeerInfo{PublicKey: record.PublicKey, connectionActive: []*Connection{connection}, connectionLatest: connection, NodeID: publicKey2NodeID(record.PublicKey), messageSequence: rand.Uint32()}
 }