p2p, p2p/discover: add signed ENR generation (#17753)

This PR adds enode.LocalNode and integrates it into the p2p
subsystem. This new object is the keeper of the local node
record. For now, a new version of the record is produced every
time the client restarts. We'll make it smarter to avoid that in
the future.

There are a couple of other changes in this commit: discovery now
waits for all of its goroutines at shutdown and the p2p server
now closes the node database after discovery has shut down. This
fixes a leveldb crash in tests. p2p server startup is faster
because it doesn't need to wait for the external IP query
anymore.

22 files changed, 966 insertions, 266 deletions

diff --git a/p2p/dial.go b/p2p/dial.go
index 359cdbcbb..d228514fc 100644
--- a/p2p/dial.go
+++ b/p2p/dial.go
@@ -71,6 +71,7 @@ type dialstate struct {
 	maxDynDials int
 	ntab        discoverTable
 	netrestrict *netutil.Netlist
+	self        enode.ID
 
 	lookupRunning bool
 	dialing       map[enode.ID]connFlag
@@ -84,7 +85,6 @@ type dialstate struct {
 }
 
 type discoverTable interface {
-	Self() *enode.Node
 	Close()
 	Resolve(*enode.Node) *enode.Node
 	LookupRandom() []*enode.Node
@@ -126,10 +126,11 @@ type waitExpireTask struct {
 	time.Duration
 }
 
-func newDialState(static []*enode.Node, bootnodes []*enode.Node, ntab discoverTable, maxdyn int, netrestrict *netutil.Netlist) *dialstate {
+func newDialState(self enode.ID, static []*enode.Node, bootnodes []*enode.Node, ntab discoverTable, maxdyn int, netrestrict *netutil.Netlist) *dialstate {
 	s := &dialstate{
 		maxDynDials: maxdyn,
 		ntab:        ntab,
+		self:        self,
 		netrestrict: netrestrict,
 		static:      make(map[enode.ID]*dialTask),
 		dialing:     make(map[enode.ID]connFlag),
@@ -266,7 +267,7 @@ func (s *dialstate) checkDial(n *enode.Node, peers map[enode.ID]*Peer) error {
 		return errAlreadyDialing
 	case peers[n.ID()] != nil:
 		return errAlreadyConnected
-	case s.ntab != nil && n.ID() == s.ntab.Self().ID():
+	case n.ID() == s.self:
 		return errSelf
 	case s.netrestrict != nil && !s.netrestrict.Contains(n.IP()):
 		return errNotWhitelisted
diff --git a/p2p/dial_test.go b/p2p/dial_test.go
index 2de2c5999..f41ab7752 100644
--- a/p2p/dial_test.go
+++ b/p2p/dial_test.go
@@ -89,7 +89,7 @@ func (t fakeTable) ReadRandomNodes(buf []*enode.Node) int { return copy(buf, t)
 // This test checks that dynamic dials are launched from discovery results.
 func TestDialStateDynDial(t *testing.T) {
 	runDialTest(t, dialtest{
-		init: newDialState(nil, nil, fakeTable{}, 5, nil),
+		init: newDialState(enode.ID{}, nil, nil, fakeTable{}, 5, nil),
 		rounds: []round{
 			// A discovery query is launched.
 			{
@@ -236,7 +236,7 @@ func TestDialStateDynDialBootnode(t *testing.T) {
 		newNode(uintID(8), nil),
 	}
 	runDialTest(t, dialtest{
-		init: newDialState(nil, bootnodes, table, 5, nil),
+		init: newDialState(enode.ID{}, nil, bootnodes, table, 5, nil),
 		rounds: []round{
 			// 2 dynamic dials attempted, bootnodes pending fallback interval
 			{
@@ -324,7 +324,7 @@ func TestDialStateDynDialFromTable(t *testing.T) {
 	}
 
 	runDialTest(t, dialtest{
-		init: newDialState(nil, nil, table, 10, nil),
+		init: newDialState(enode.ID{}, nil, nil, table, 10, nil),
 		rounds: []round{
 			// 5 out of 8 of the nodes returned by ReadRandomNodes are dialed.
 			{
@@ -430,7 +430,7 @@ func TestDialStateNetRestrict(t *testing.T) {
 	restrict.Add("127.0.2.0/24")
 
 	runDialTest(t, dialtest{
-		init: newDialState(nil, nil, table, 10, restrict),
+		init: newDialState(enode.ID{}, nil, nil, table, 10, restrict),
 		rounds: []round{
 			{
 				new: []task{
@@ -453,7 +453,7 @@ func TestDialStateStaticDial(t *testing.T) {
 	}
 
 	runDialTest(t, dialtest{
-		init: newDialState(wantStatic, nil, fakeTable{}, 0, nil),
+		init: newDialState(enode.ID{}, wantStatic, nil, fakeTable{}, 0, nil),
 		rounds: []round{
 			// Static dials are launched for the nodes that
 			// aren't yet connected.
@@ -557,7 +557,7 @@ func TestDialStaticAfterReset(t *testing.T) {
 		},
 	}
 	dTest := dialtest{
-		init:   newDialState(wantStatic, nil, fakeTable{}, 0, nil),
+		init:   newDialState(enode.ID{}, wantStatic, nil, fakeTable{}, 0, nil),
 		rounds: rounds,
 	}
 	runDialTest(t, dTest)
@@ -578,7 +578,7 @@ func TestDialStateCache(t *testing.T) {
 	}
 
 	runDialTest(t, dialtest{
-		init: newDialState(wantStatic, nil, fakeTable{}, 0, nil),
+		init: newDialState(enode.ID{}, wantStatic, nil, fakeTable{}, 0, nil),
 		rounds: []round{
 			// Static dials are launched for the nodes that
 			// aren't yet connected.
@@ -640,7 +640,7 @@ func TestDialStateCache(t *testing.T) {
 func TestDialResolve(t *testing.T) {
 	resolved := newNode(uintID(1), net.IP{127, 0, 55, 234})
 	table := &resolveMock{answer: resolved}
-	state := newDialState(nil, nil, table, 0, nil)
+	state := newDialState(enode.ID{}, nil, nil, table, 0, nil)
 
 	// Check that the task is generated with an incomplete ID.
 	dest := newNode(uintID(1), nil)
diff --git a/p2p/discover/table.go b/p2p/discover/table.go
index 7a3e41de1..afd4c9a27 100644
--- a/p2p/discover/table.go
+++ b/p2p/discover/table.go
@@ -72,21 +72,20 @@ type Table struct {
 	ips     netutil.DistinctNetSet
 
 	db         *enode.DB // database of known nodes
+	net        transport
 	refreshReq chan chan struct{}
 	initDone   chan struct{}
 	closeReq   chan struct{}
 	closed     chan struct{}
 
 	nodeAddedHook func(*node) // for testing
-
-	net  transport
-	self *node // metadata of the local node
 }
 
 // transport is implemented by the UDP transport.
 // it is an interface so we can test without opening lots of UDP
 // sockets and without generating a private key.
 type transport interface {
+	self() *enode.Node
 	ping(enode.ID, *net.UDPAddr) error
 	findnode(toid enode.ID, addr *net.UDPAddr, target encPubkey) ([]*node, error)
 	close()
@@ -100,11 +99,10 @@ type bucket struct {
 	ips          netutil.DistinctNetSet
 }
 
-func newTable(t transport, self *enode.Node, db *enode.DB, bootnodes []*enode.Node) (*Table, error) {
+func newTable(t transport, db *enode.DB, bootnodes []*enode.Node) (*Table, error) {
 	tab := &Table{
 		net:        t,
 		db:         db,
-		self:       wrapNode(self),
 		refreshReq: make(chan chan struct{}),
 		initDone:   make(chan struct{}),
 		closeReq:   make(chan struct{}),
@@ -127,6 +125,10 @@ func newTable(t transport, self *enode.Node, db *enode.DB, bootnodes []*enode.No
 	return tab, nil
 }
 
+func (tab *Table) self() *enode.Node {
+	return tab.net.self()
+}
+
 func (tab *Table) seedRand() {
 	var b [8]byte
 	crand.Read(b[:])
@@ -136,11 +138,6 @@ func (tab *Table) seedRand() {
 	tab.mutex.Unlock()
 }
 
-// Self returns the local node.
-func (tab *Table) Self() *enode.Node {
-	return unwrapNode(tab.self)
-}
-
 // ReadRandomNodes fills the given slice with random nodes from the table. The results
 // are guaranteed to be unique for a single invocation, no node will appear twice.
 func (tab *Table) ReadRandomNodes(buf []*enode.Node) (n int) {
@@ -183,6 +180,10 @@ func (tab *Table) ReadRandomNodes(buf []*enode.Node) (n int) {
 
 // Close terminates the network listener and flushes the node database.
 func (tab *Table) Close() {
+	if tab.net != nil {
+		tab.net.close()
+	}
+
 	select {
 	case <-tab.closed:
 		// already closed.
@@ -257,7 +258,7 @@ func (tab *Table) lookup(targetKey encPubkey, refreshIfEmpty bool) []*node {
 	)
 	// don't query further if we hit ourself.
 	// unlikely to happen often in practice.
-	asked[tab.self.ID()] = true
+	asked[tab.self().ID()] = true
 
 	for {
 		tab.mutex.Lock()
@@ -340,8 +341,8 @@ func (tab *Table) loop() {
 		revalidate     = time.NewTimer(tab.nextRevalidateTime())
 		refresh        = time.NewTicker(refreshInterval)
 		copyNodes      = time.NewTicker(copyNodesInterval)
-		revalidateDone = make(chan struct{})
 		refreshDone    = make(chan struct{})           // where doRefresh reports completion
+		revalidateDone chan struct{}                   // where doRevalidate reports completion
 		waiting        = []chan struct{}{tab.initDone} // holds waiting callers while doRefresh runs
 	)
 	defer refresh.Stop()
@@ -372,9 +373,11 @@ loop:
 			}
 			waiting, refreshDone = nil, nil
 		case <-revalidate.C:
+			revalidateDone = make(chan struct{})
 			go tab.doRevalidate(revalidateDone)
 		case <-revalidateDone:
 			revalidate.Reset(tab.nextRevalidateTime())
+			revalidateDone = nil
 		case <-copyNodes.C:
 			go tab.copyLiveNodes()
 		case <-tab.closeReq:
@@ -382,15 +385,15 @@ loop:
 		}
 	}
 
-	if tab.net != nil {
-		tab.net.close()
-	}
 	if refreshDone != nil {
 		<-refreshDone
 	}
 	for _, ch := range waiting {
 		close(ch)
 	}
+	if revalidateDone != nil {
+		<-revalidateDone
+	}
 	close(tab.closed)
 }
 
@@ -408,7 +411,7 @@ func (tab *Table) doRefresh(done chan struct{}) {
 	// Run self lookup to discover new neighbor nodes.
 	// We can only do this if we have a secp256k1 identity.
 	var key ecdsa.PublicKey
-	if err := tab.self.Load((*enode.Secp256k1)(&key)); err == nil {
+	if err := tab.self().Load((*enode.Secp256k1)(&key)); err == nil {
 		tab.lookup(encodePubkey(&key), false)
 	}
 
@@ -530,7 +533,7 @@ func (tab *Table) len() (n int) {
 
 // bucket returns the bucket for the given node ID hash.
 func (tab *Table) bucket(id enode.ID) *bucket {
-	d := enode.LogDist(tab.self.ID(), id)
+	d := enode.LogDist(tab.self().ID(), id)
 	if d <= bucketMinDistance {
 		return tab.buckets[0]
 	}
@@ -543,7 +546,7 @@ func (tab *Table) bucket(id enode.ID) *bucket {
 //
 // The caller must not hold tab.mutex.
 func (tab *Table) add(n *node) {
-	if n.ID() == tab.self.ID() {
+	if n.ID() == tab.self().ID() {
 		return
 	}
 
@@ -576,7 +579,7 @@ func (tab *Table) stuff(nodes []*node) {
 	defer tab.mutex.Unlock()
 
 	for _, n := range nodes {
-		if n.ID() == tab.self.ID() {
+		if n.ID() == tab.self().ID() {
 			continue // don't add self
 		}
 		b := tab.bucket(n.ID())
diff --git a/p2p/discover/table_test.go b/p2p/discover/table_test.go
index e8631024b..6b4cd2d18 100644
--- a/p2p/discover/table_test.go
+++ b/p2p/discover/table_test.go
@@ -141,7 +141,7 @@ func TestTable_IPLimit(t *testing.T) {
 	defer db.Close()
 
 	for i := 0; i < tableIPLimit+1; i++ {
-		n := nodeAtDistance(tab.self.ID(), i, net.IP{172, 0, 1, byte(i)})
+		n := nodeAtDistance(tab.self().ID(), i, net.IP{172, 0, 1, byte(i)})
 		tab.add(n)
 	}
 	if tab.len() > tableIPLimit {
@@ -158,7 +158,7 @@ func TestTable_BucketIPLimit(t *testing.T) {
 
 	d := 3
 	for i := 0; i < bucketIPLimit+1; i++ {
-		n := nodeAtDistance(tab.self.ID(), d, net.IP{172, 0, 1, byte(i)})
+		n := nodeAtDistance(tab.self().ID(), d, net.IP{172, 0, 1, byte(i)})
 		tab.add(n)
 	}
 	if tab.len() > bucketIPLimit {
@@ -240,7 +240,7 @@ func TestTable_ReadRandomNodesGetAll(t *testing.T) {
 
 		for i := 0; i < len(buf); i++ {
 			ld := cfg.Rand.Intn(len(tab.buckets))
-			tab.stuff([]*node{nodeAtDistance(tab.self.ID(), ld, intIP(ld))})
+			tab.stuff([]*node{nodeAtDistance(tab.self().ID(), ld, intIP(ld))})
 		}
 		gotN := tab.ReadRandomNodes(buf)
 		if gotN != tab.len() {
@@ -510,6 +510,10 @@ type preminedTestnet struct {
 	dists     [hashBits + 1][]encPubkey
 }
 
+func (tn *preminedTestnet) self() *enode.Node {
+	return nullNode
+}
+
 func (tn *preminedTestnet) findnode(toid enode.ID, toaddr *net.UDPAddr, target encPubkey) ([]*node, error) {
 	// current log distance is encoded in port number
 	// fmt.Println("findnode query at dist", toaddr.Port)
diff --git a/p2p/discover/table_util_test.go b/p2p/discover/table_util_test.go
index 05ae0b6c0..d41519452 100644
--- a/p2p/discover/table_util_test.go
+++ b/p2p/discover/table_util_test.go
@@ -28,12 +28,17 @@ import (
 	"github.com/ethereum/go-ethereum/p2p/enr"
 )
 
-func newTestTable(t transport) (*Table, *enode.DB) {
+var nullNode *enode.Node
+
+func init() {
 	var r enr.Record
 	r.Set(enr.IP{0, 0, 0, 0})
-	n := enode.SignNull(&r, enode.ID{})
+	nullNode = enode.SignNull(&r, enode.ID{})
+}
+
+func newTestTable(t transport) (*Table, *enode.DB) {
 	db, _ := enode.OpenDB("")
-	tab, _ := newTable(t, n, db, nil)
+	tab, _ := newTable(t, db, nil)
 	return tab, db
 }
 
@@ -70,10 +75,10 @@ func intIP(i int) net.IP {
 
 // fillBucket inserts nodes into the given bucket until it is full.
 func fillBucket(tab *Table, n *node) (last *node) {
-	ld := enode.LogDist(tab.self.ID(), n.ID())
+	ld := enode.LogDist(tab.self().ID(), n.ID())
 	b := tab.bucket(n.ID())
 	for len(b.entries) < bucketSize {
-		b.entries = append(b.entries, nodeAtDistance(tab.self.ID(), ld, intIP(ld)))
+		b.entries = append(b.entries, nodeAtDistance(tab.self().ID(), ld, intIP(ld)))
 	}
 	return b.entries[bucketSize-1]
 }
@@ -81,15 +86,25 @@ func fillBucket(tab *Table, n *node) (last *node) {
 type pingRecorder struct {
 	mu           sync.Mutex
 	dead, pinged map[enode.ID]bool
+	n            *enode.Node
 }
 
 func newPingRecorder() *pingRecorder {
+	var r enr.Record
+	r.Set(enr.IP{0, 0, 0, 0})
+	n := enode.SignNull(&r, enode.ID{})
+
 	return &pingRecorder{
 		dead:   make(map[enode.ID]bool),
 		pinged: make(map[enode.ID]bool),
+		n:      n,
 	}
 }
 
+func (t *pingRecorder) self() *enode.Node {
+	return nullNode
+}
+
 func (t *pingRecorder) findnode(toid enode.ID, toaddr *net.UDPAddr, target encPubkey) ([]*node, error) {
 	return nil, nil
 }
diff --git a/p2p/discover/udp.go b/p2p/discover/udp.go
index 45fcce282..37a044902 100644
--- a/p2p/discover/udp.go
+++ b/p2p/discover/udp.go
@@ -23,12 +23,12 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"sync"
 	"time"
 
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/p2p/enode"
-	"github.com/ethereum/go-ethereum/p2p/nat"
 	"github.com/ethereum/go-ethereum/p2p/netutil"
 	"github.com/ethereum/go-ethereum/rlp"
 )
@@ -118,9 +118,11 @@ type (
 )
 
 func makeEndpoint(addr *net.UDPAddr, tcpPort uint16) rpcEndpoint {
-	ip := addr.IP.To4()
-	if ip == nil {
-		ip = addr.IP.To16()
+	ip := net.IP{}
+	if ip4 := addr.IP.To4(); ip4 != nil {
+		ip = ip4
+	} else if ip6 := addr.IP.To16(); ip6 != nil {
+		ip = ip6
 	}
 	return rpcEndpoint{IP: ip, UDP: uint16(addr.Port), TCP: tcpPort}
 }
@@ -165,20 +167,19 @@ type conn interface {
 	LocalAddr() net.Addr
 }
 
-// udp implements the RPC protocol.
+// udp implements the discovery v4 UDP wire protocol.
 type udp struct {
 	conn        conn
 	netrestrict *netutil.Netlist
 	priv        *ecdsa.PrivateKey
-	ourEndpoint rpcEndpoint
+	localNode   *enode.LocalNode
+	db          *enode.DB
+	tab         *Table
+	wg          sync.WaitGroup
 
 	addpending chan *pending
 	gotreply   chan reply
-
-	closing chan struct{}
-	nat     nat.Interface
-
-	*Table
+	closing    chan struct{}
 }
 
 // pending represents a pending reply.
@@ -230,60 +231,57 @@ type Config struct {
 	PrivateKey *ecdsa.PrivateKey
 
 	// These settings are optional:
-	AnnounceAddr *net.UDPAddr      // local address announced in the DHT
-	NodeDBPath   string            // if set, the node database is stored at this filesystem location
-	NetRestrict  *netutil.Netlist  // network whitelist
-	Bootnodes    []*enode.Node     // list of bootstrap nodes
-	Unhandled    chan<- ReadPacket // unhandled packets are sent on this channel
+	NetRestrict *netutil.Netlist  // network whitelist
+	Bootnodes   []*enode.Node     // list of bootstrap nodes
+	Unhandled   chan<- ReadPacket // unhandled packets are sent on this channel
 }
 
 // ListenUDP returns a new table that listens for UDP packets on laddr.
-func ListenUDP(c conn, cfg Config) (*Table, error) {
-	tab, _, err := newUDP(c, cfg)
+func ListenUDP(c conn, ln *enode.LocalNode, cfg Config) (*Table, error) {
+	tab, _, err := newUDP(c, ln, cfg)
 	if err != nil {
 		return nil, err
 	}
-	log.Info("UDP listener up", "self", tab.self)
 	return tab, nil
 }
 
-func newUDP(c conn, cfg Config) (*Table, *udp, error) {
-	realaddr := c.LocalAddr().(*net.UDPAddr)
-	if cfg.AnnounceAddr != nil {
-		realaddr = cfg.AnnounceAddr
-	}
-	self := enode.NewV4(&cfg.PrivateKey.PublicKey, realaddr.IP, realaddr.Port, realaddr.Port)
-	db, err := enode.OpenDB(cfg.NodeDBPath)
-	if err != nil {
-		return nil, nil, err
-	}
-
+func newUDP(c conn, ln *enode.LocalNode, cfg Config) (*Table, *udp, error) {
 	udp := &udp{
 		conn:        c,
 		priv:        cfg.PrivateKey,
 		netrestrict: cfg.NetRestrict,
+		localNode:   ln,
+		db:          ln.Database(),
 		closing:     make(chan struct{}),
 		gotreply:    make(chan reply),
 		addpending:  make(chan *pending),
 	}
-	// TODO: separate TCP port
-	udp.ourEndpoint = makeEndpoint(realaddr, uint16(realaddr.Port))
-	tab, err := newTable(udp, self, db, cfg.Bootnodes)
+	tab, err := newTable(udp, ln.Database(), cfg.Bootnodes)
 	if err != nil {
 		return nil, nil, err
 	}
-	udp.Table = tab
+	udp.tab = tab
 
+	udp.wg.Add(2)
 	go udp.loop()
 	go udp.readLoop(cfg.Unhandled)
-	return udp.Table, udp, nil
+	return udp.tab, udp, nil
+}
+
+func (t *udp) self() *enode.Node {
+	return t.localNode.Node()
 }
 
 func (t *udp) close() {
 	close(t.closing)
 	t.conn.Close()
-	t.db.Close()
-	// TODO: wait for the loops to end.
+	t.wg.Wait()
+}
+
+func (t *udp) ourEndpoint() rpcEndpoint {
+	n := t.self()
+	a := &net.UDPAddr{IP: n.IP(), Port: n.UDP()}
+	return makeEndpoint(a, uint16(n.TCP()))
 }
 
 // ping sends a ping message to the given node and waits for a reply.
@@ -296,7 +294,7 @@ func (t *udp) ping(toid enode.ID, toaddr *net.UDPAddr) error {
 func (t *udp) sendPing(toid enode.ID, toaddr *net.UDPAddr, callback func()) <-chan error {
 	req := &ping{
 		Version:    4,
-		From:       t.ourEndpoint,
+		From:       t.ourEndpoint(),
 		To:         makeEndpoint(toaddr, 0), // TODO: maybe use known TCP port from DB
 		Expiration: uint64(time.Now().Add(expiration).Unix()),
 	}
@@ -313,6 +311,7 @@ func (t *udp) sendPing(toid enode.ID, toaddr *net.UDPAddr, callback func()) <-ch
 		}
 		return ok
 	})
+	t.localNode.UDPContact(toaddr)
 	t.write(toaddr, req.name(), packet)
 	return errc
 }
@@ -381,6 +380,8 @@ func (t *udp) handleReply(from enode.ID, ptype byte, req packet) bool {
 // loop runs in its own goroutine. it keeps track of
 // the refresh timer and the pending reply queue.
 func (t *udp) loop() {
+	defer t.wg.Done()
+
 	var (
 		plist        = list.New()
 		timeout      = time.NewTimer(0)
@@ -542,10 +543,11 @@ func encodePacket(priv *ecdsa.PrivateKey, ptype byte, req interface{}) (packet,
 
 // readLoop runs in its own goroutine. it handles incoming UDP packets.
 func (t *udp) readLoop(unhandled chan<- ReadPacket) {
-	defer t.conn.Close()
+	defer t.wg.Done()
 	if unhandled != nil {
 		defer close(unhandled)
 	}
+
 	// Discovery packets are defined to be no larger than 1280 bytes.
 	// Packets larger than this size will be cut at the end and treated
 	// as invalid because their hash won't match.
@@ -629,10 +631,11 @@ func (req *ping) handle(t *udp, from *net.UDPAddr, fromKey encPubkey, mac []byte
 	n := wrapNode(enode.NewV4(key, from.IP, int(req.From.TCP), from.Port))
 	t.handleReply(n.ID(), pingPacket, req)
 	if time.Since(t.db.LastPongReceived(n.ID())) > bondExpiration {
-		t.sendPing(n.ID(), from, func() { t.addThroughPing(n) })
+		t.sendPing(n.ID(), from, func() { t.tab.addThroughPing(n) })
 	} else {
-		t.addThroughPing(n)
+		t.tab.addThroughPing(n)
 	}
+	t.localNode.UDPEndpointStatement(from, &net.UDPAddr{IP: req.To.IP, Port: int(req.To.UDP)})
 	t.db.UpdateLastPingReceived(n.ID(), time.Now())
 	return nil
 }
@@ -647,6 +650,7 @@ func (req *pong) handle(t *udp, from *net.UDPAddr, fromKey encPubkey, mac []byte
 	if !t.handleReply(fromID, pongPacket, req) {
 		return errUnsolicitedReply
 	}
+	t.localNode.UDPEndpointStatement(from, &net.UDPAddr{IP: req.To.IP, Port: int(req.To.UDP)})
 	t.db.UpdateLastPongReceived(fromID, time.Now())
 	return nil
 }
@@ -668,9 +672,9 @@ func (req *findnode) handle(t *udp, from *net.UDPAddr, fromKey encPubkey, mac []
 		return errUnknownNode
 	}
 	target := enode.ID(crypto.Keccak256Hash(req.Target[:]))
-	t.mutex.Lock()
-	closest := t.closest(target, bucketSize).entries
-	t.mutex.Unlock()
+	t.tab.mutex.Lock()
+	closest := t.tab.closest(target, bucketSize).entries
+	t.tab.mutex.Unlock()
 
 	p := neighbors{Expiration: uint64(time.Now().Add(expiration).Unix())}
 	var sent bool
diff --git a/p2p/discover/udp_test.go b/p2p/discover/udp_test.go
index da95c4f5c..a4ddaf750 100644
--- a/p2p/discover/udp_test.go
+++ b/p2p/discover/udp_test.go
@@ -71,7 +71,9 @@ func newUDPTest(t *testing.T) *udpTest {
 		remotekey:  newkey(),
 		remoteaddr: &net.UDPAddr{IP: net.IP{10, 0, 1, 99}, Port: 30303},
 	}
-	test.table, test.udp, _ = newUDP(test.pipe, Config{PrivateKey: test.localkey})
+	db, _ := enode.OpenDB("")
+	ln := enode.NewLocalNode(db, test.localkey)
+	test.table, test.udp, _ = newUDP(test.pipe, ln, Config{PrivateKey: test.localkey})
 	// Wait for initial refresh so the table doesn't send unexpected findnode.
 	<-test.table.initDone
 	return test
@@ -355,12 +357,13 @@ func TestUDP_successfulPing(t *testing.T) {
 
 	// remote is unknown, the table pings back.
 	hash, _ := test.waitPacketOut(func(p *ping) error {
-		if !reflect.DeepEqual(p.From, test.udp.ourEndpoint) {
-			t.Errorf("got ping.From %v, want %v", p.From, test.udp.ourEndpoint)
+		if !reflect.DeepEqual(p.From, test.udp.ourEndpoint()) {
+			t.Errorf("got ping.From %#v, want %#v", p.From, test.udp.ourEndpoint())
 		}
 		wantTo := rpcEndpoint{
 			// The mirrored UDP address is the UDP packet sender.
-			IP: test.remoteaddr.IP, UDP: uint16(test.remoteaddr.Port),
+			IP:  test.remoteaddr.IP,
+			UDP: uint16(test.remoteaddr.Port),
 			TCP: 0,
 		}
 		if !reflect.DeepEqual(p.To, wantTo) {
diff --git a/p2p/discv5/udp.go b/p2p/discv5/udp.go
index 49e1cb811..ff5ed983b 100644
--- a/p2p/discv5/udp.go
+++ b/p2p/discv5/udp.go
@@ -230,7 +230,8 @@ type udp struct {
 }
 
 // ListenUDP returns a new table that listens for UDP packets on laddr.
-func ListenUDP(priv *ecdsa.PrivateKey, conn conn, realaddr *net.UDPAddr, nodeDBPath string, netrestrict *netutil.Netlist) (*Network, error) {
+func ListenUDP(priv *ecdsa.PrivateKey, conn conn, nodeDBPath string, netrestrict *netutil.Netlist) (*Network, error) {
+	realaddr := conn.LocalAddr().(*net.UDPAddr)
 	transport, err := listenUDP(priv, conn, realaddr)
 	if err != nil {
 		return nil, err
diff --git a/p2p/enode/localnode.go b/p2p/enode/localnode.go
new file mode 100644
index 000000000..623f8eae1
--- /dev/null
+++ b/p2p/enode/localnode.go
@@ -0,0 +1,246 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package enode
+
+import (
+	"crypto/ecdsa"
+	"fmt"
+	"net"
+	"reflect"
+	"strconv"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/p2p/enr"
+	"github.com/ethereum/go-ethereum/p2p/netutil"
+)
+
+const (
+	// IP tracker configuration
+	iptrackMinStatements = 10
+	iptrackWindow        = 5 * time.Minute
+	iptrackContactWindow = 10 * time.Minute
+)
+
+// LocalNode produces the signed node record of a local node, i.e. a node run in the
+// current process. Setting ENR entries via the Set method updates the record. A new version
+// of the record is signed on demand when the Node method is called.
+type LocalNode struct {
+	cur atomic.Value // holds a non-nil node pointer while the record is up-to-date.
+	id  ID
+	key *ecdsa.PrivateKey
+	db  *DB
+
+	// everything below is protected by a lock
+	mu          sync.Mutex
+	seq         uint64
+	entries     map[string]enr.Entry
+	udpTrack    *netutil.IPTracker // predicts external UDP endpoint
+	staticIP    net.IP
+	fallbackIP  net.IP
+	fallbackUDP int
+}
+
+// NewLocalNode creates a local node.
+func NewLocalNode(db *DB, key *ecdsa.PrivateKey) *LocalNode {
+	ln := &LocalNode{
+		id:       PubkeyToIDV4(&key.PublicKey),
+		db:       db,
+		key:      key,
+		udpTrack: netutil.NewIPTracker(iptrackWindow, iptrackContactWindow, iptrackMinStatements),
+		entries:  make(map[string]enr.Entry),
+	}
+	ln.seq = db.localSeq(ln.id)
+	ln.invalidate()
+	return ln
+}
+
+// Database returns the node database associated with the local node.
+func (ln *LocalNode) Database() *DB {
+	return ln.db
+}
+
+// Node returns the current version of the local node record.
+func (ln *LocalNode) Node() *Node {
+	n := ln.cur.Load().(*Node)
+	if n != nil {
+		return n
+	}
+	// Record was invalidated, sign a new copy.
+	ln.mu.Lock()
+	defer ln.mu.Unlock()
+	ln.sign()
+	return ln.cur.Load().(*Node)
+}
+
+// ID returns the local node ID.
+func (ln *LocalNode) ID() ID {
+	return ln.id
+}
+
+// Set puts the given entry into the local record, overwriting
+// any existing value.
+func (ln *LocalNode) Set(e enr.Entry) {
+	ln.mu.Lock()
+	defer ln.mu.Unlock()
+
+	ln.set(e)
+}
+
+func (ln *LocalNode) set(e enr.Entry) {
+	val, exists := ln.entries[e.ENRKey()]
+	if !exists || !reflect.DeepEqual(val, e) {
+		ln.entries[e.ENRKey()] = e
+		ln.invalidate()
+	}
+}
+
+// Delete removes the given entry from the local record.
+func (ln *LocalNode) Delete(e enr.Entry) {
+	ln.mu.Lock()
+	defer ln.mu.Unlock()
+
+	ln.delete(e)
+}
+
+func (ln *LocalNode) delete(e enr.Entry) {
+	_, exists := ln.entries[e.ENRKey()]
+	if exists {
+		delete(ln.entries, e.ENRKey())
+		ln.invalidate()
+	}
+}
+
+// SetStaticIP sets the local IP to the given one unconditionally.
+// This disables endpoint prediction.
+func (ln *LocalNode) SetStaticIP(ip net.IP) {
+	ln.mu.Lock()
+	defer ln.mu.Unlock()
+
+	ln.staticIP = ip
+	ln.updateEndpoints()
+}
+
+// SetFallbackIP sets the last-resort IP address. This address is used
+// if no endpoint prediction can be made and no static IP is set.
+func (ln *LocalNode) SetFallbackIP(ip net.IP) {
+	ln.mu.Lock()
+	defer ln.mu.Unlock()
+
+	ln.fallbackIP = ip
+	ln.updateEndpoints()
+}
+
+// SetFallbackUDP sets the last-resort UDP port. This port is used
+// if no endpoint prediction can be made.
+func (ln *LocalNode) SetFallbackUDP(port int) {
+	ln.mu.Lock()
+	defer ln.mu.Unlock()
+
+	ln.fallbackUDP = port
+	ln.updateEndpoints()
+}
+
+// UDPEndpointStatement should be called whenever a statement about the local node's
+// UDP endpoint is received. It feeds the local endpoint predictor.
+func (ln *LocalNode) UDPEndpointStatement(fromaddr, endpoint *net.UDPAddr) {
+	ln.mu.Lock()
+	defer ln.mu.Unlock()
+
+	ln.udpTrack.AddStatement(fromaddr.String(), endpoint.String())
+	ln.updateEndpoints()
+}
+
+// UDPContact should be called whenever the local node has announced itself to another node
+// via UDP. It feeds the local endpoint predictor.
+func (ln *LocalNode) UDPContact(toaddr *net.UDPAddr) {
+	ln.mu.Lock()
+	defer ln.mu.Unlock()
+
+	ln.udpTrack.AddContact(toaddr.String())
+	ln.updateEndpoints()
+}
+
+func (ln *LocalNode) updateEndpoints() {
+	// Determine the endpoints.
+	newIP := ln.fallbackIP
+	newUDP := ln.fallbackUDP
+	if ln.staticIP != nil {
+		newIP = ln.staticIP
+	} else if ip, port := predictAddr(ln.udpTrack); ip != nil {
+		newIP = ip
+		newUDP = port
+	}
+
+	// Update the record.
+	if newIP != nil && !newIP.IsUnspecified() {
+		ln.set(enr.IP(newIP))
+		if newUDP != 0 {
+			ln.set(enr.UDP(newUDP))
+		} else {
+			ln.delete(enr.UDP(0))
+		}
+	} else {
+		ln.delete(enr.IP{})
+	}
+}
+
+// predictAddr wraps IPTracker.PredictEndpoint, converting from its string-based
+// endpoint representation to IP and port types.
+func predictAddr(t *netutil.IPTracker) (net.IP, int) {
+	ep := t.PredictEndpoint()
+	if ep == "" {
+		return nil, 0
+	}
+	ipString, portString, _ := net.SplitHostPort(ep)
+	ip := net.ParseIP(ipString)
+	port, _ := strconv.Atoi(portString)
+	return ip, port
+}
+
+func (ln *LocalNode) invalidate() {
+	ln.cur.Store((*Node)(nil))
+}
+
+func (ln *LocalNode) sign() {
+	if n := ln.cur.Load().(*Node); n != nil {
+		return // no changes
+	}
+
+	var r enr.Record
+	for _, e := range ln.entries {
+		r.Set(e)
+	}
+	ln.bumpSeq()
+	r.SetSeq(ln.seq)
+	if err := SignV4(&r, ln.key); err != nil {
+		panic(fmt.Errorf("enode: can't sign record: %v", err))
+	}
+	n, err := New(ValidSchemes, &r)
+	if err != nil {
+		panic(fmt.Errorf("enode: can't verify local record: %v", err))
+	}
+	ln.cur.Store(n)
+	log.Info("New local node record", "seq", ln.seq, "id", n.ID(), "ip", n.IP(), "udp", n.UDP(), "tcp", n.TCP())
+}
+
+func (ln *LocalNode) bumpSeq() {
+	ln.seq++
+	ln.db.storeLocalSeq(ln.id, ln.seq)
+}
diff --git a/p2p/enode/localnode_test.go b/p2p/enode/localnode_test.go
new file mode 100644
index 000000000..f5e3496d6
--- /dev/null
+++ b/p2p/enode/localnode_test.go
@@ -0,0 +1,76 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package enode
+
+import (
+	"testing"
+
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/p2p/enr"
+)
+
+func newLocalNodeForTesting() (*LocalNode, *DB) {
+	db, _ := OpenDB("")
+	key, _ := crypto.GenerateKey()
+	return NewLocalNode(db, key), db
+}
+
+func TestLocalNode(t *testing.T) {
+	ln, db := newLocalNodeForTesting()
+	defer db.Close()
+
+	if ln.Node().ID() != ln.ID() {
+		t.Fatal("inconsistent ID")
+	}
+
+	ln.Set(enr.WithEntry("x", uint(3)))
+	var x uint
+	if err := ln.Node().Load(enr.WithEntry("x", &x)); err != nil {
+		t.Fatal("can't load entry 'x':", err)
+	} else if x != 3 {
+		t.Fatal("wrong value for entry 'x':", x)
+	}
+}
+
+func TestLocalNodeSeqPersist(t *testing.T) {
+	ln, db := newLocalNodeForTesting()
+	defer db.Close()
+
+	if s := ln.Node().Seq(); s != 1 {
+		t.Fatalf("wrong initial seq %d, want 1", s)
+	}
+	ln.Set(enr.WithEntry("x", uint(1)))
+	if s := ln.Node().Seq(); s != 2 {
+		t.Fatalf("wrong seq %d after set, want 2", s)
+	}
+
+	// Create a new instance, it should reload the sequence number.
+	// The number increases just after that because a new record is
+	// created without the "x" entry.
+	ln2 := NewLocalNode(db, ln.key)
+	if s := ln2.Node().Seq(); s != 3 {
+		t.Fatalf("wrong seq %d on new instance, want 3", s)
+	}
+
+	// Create a new instance with a different node key on the same database.
+	// This should reset the sequence number.
+	key, _ := crypto.GenerateKey()
+	ln3 := NewLocalNode(db, key)
+	if s := ln3.Node().Seq(); s != 1 {
+		t.Fatalf("wrong seq %d on instance with changed key, want 1", s)
+	}
+}
diff --git a/p2p/enode/node.go b/p2p/enode/node.go
index 84088fcd2..b454ab255 100644
--- a/p2p/enode/node.go
+++ b/p2p/enode/node.go
@@ -98,6 +98,13 @@ func (n *Node) Pubkey() *ecdsa.PublicKey {
 	return &key
 }
 
+// Record returns the node's record. The return value is a copy and may
+// be modified by the caller.
+func (n *Node) Record() *enr.Record {
+	cpy := n.r
+	return &cpy
+}
+
 // checks whether n is a valid complete node.
 func (n *Node) ValidateComplete() error {
 	if n.Incomplete() {
diff --git a/p2p/enode/nodedb.go b/p2p/enode/nodedb.go
index a929b75d7..7ee0c09a9 100644
--- a/p2p/enode/nodedb.go
+++ b/p2p/enode/nodedb.go
@@ -35,11 +35,24 @@ import (
 	"github.com/syndtr/goleveldb/leveldb/util"
 )
 
+// Keys in the node database.
+const (
+	dbVersionKey = "version" // Version of the database to flush if changes
+	dbItemPrefix = "n:"      // Identifier to prefix node entries with
+
+	dbDiscoverRoot      = ":discover"
+	dbDiscoverSeq       = dbDiscoverRoot + ":seq"
+	dbDiscoverPing      = dbDiscoverRoot + ":lastping"
+	dbDiscoverPong      = dbDiscoverRoot + ":lastpong"
+	dbDiscoverFindFails = dbDiscoverRoot + ":findfail"
+	dbLocalRoot         = ":local"
+	dbLocalSeq          = dbLocalRoot + ":seq"
+)
+
 var (
-	nodeDBNilID          = ID{}           // Special node ID to use as a nil element.
-	nodeDBNodeExpiration = 24 * time.Hour // Time after which an unseen node should be dropped.
-	nodeDBCleanupCycle   = time.Hour      // Time period for running the expiration task.
-	nodeDBVersion        = 6
+	dbNodeExpiration = 24 * time.Hour // Time after which an unseen node should be dropped.
+	dbCleanupCycle   = time.Hour      // Time period for running the expiration task.
+	dbVersion        = 7
 )
 
 // DB is the node database, storing previously seen nodes and any collected metadata about
@@ -50,17 +63,6 @@ type DB struct {
 	quit   chan struct{} // Channel to signal the expiring thread to stop
 }
 
-// Schema layout for the node database
-var (
-	nodeDBVersionKey = []byte("version") // Version of the database to flush if changes
-	nodeDBItemPrefix = []byte("n:")      // Identifier to prefix node entries with
-
-	nodeDBDiscoverRoot      = ":discover"
-	nodeDBDiscoverPing      = nodeDBDiscoverRoot + ":lastping"
-	nodeDBDiscoverPong      = nodeDBDiscoverRoot + ":lastpong"
-	nodeDBDiscoverFindFails = nodeDBDiscoverRoot + ":findfail"
-)
-
 // OpenDB opens a node database for storing and retrieving infos about known peers in the
 // network. If no path is given an in-memory, temporary database is constructed.
 func OpenDB(path string) (*DB, error) {
@@ -93,13 +95,13 @@ func newPersistentDB(path string) (*DB, error) {
 	// The nodes contained in the cache correspond to a certain protocol version.
 	// Flush all nodes if the version doesn't match.
 	currentVer := make([]byte, binary.MaxVarintLen64)
-	currentVer = currentVer[:binary.PutVarint(currentVer, int64(nodeDBVersion))]
+	currentVer = currentVer[:binary.PutVarint(currentVer, int64(dbVersion))]
 
-	blob, err := db.Get(nodeDBVersionKey, nil)
+	blob, err := db.Get([]byte(dbVersionKey), nil)
 	switch err {
 	case leveldb.ErrNotFound:
 		// Version not found (i.e. empty cache), insert it
-		if err := db.Put(nodeDBVersionKey, currentVer, nil); err != nil {
+		if err := db.Put([]byte(dbVersionKey), currentVer, nil); err != nil {
 			db.Close()
 			return nil, err
 		}
@@ -120,28 +122,27 @@ func newPersistentDB(path string) (*DB, error) {
 // makeKey generates the leveldb key-blob from a node id and its particular
 // field of interest.
 func makeKey(id ID, field string) []byte {
-	if bytes.Equal(id[:], nodeDBNilID[:]) {
+	if (id == ID{}) {
 		return []byte(field)
 	}
-	return append(nodeDBItemPrefix, append(id[:], field...)...)
+	return append([]byte(dbItemPrefix), append(id[:], field...)...)
 }
 
 // splitKey tries to split a database key into a node id and a field part.
 func splitKey(key []byte) (id ID, field string) {
 	// If the key is not of a node, return it plainly
-	if !bytes.HasPrefix(key, nodeDBItemPrefix) {
+	if !bytes.HasPrefix(key, []byte(dbItemPrefix)) {
 		return ID{}, string(key)
 	}
 	// Otherwise split the id and field
-	item := key[len(nodeDBItemPrefix):]
+	item := key[len(dbItemPrefix):]
 	copy(id[:], item[:len(id)])
 	field = string(item[len(id):])
 
 	return id, field
 }
 
-// fetchInt64 retrieves an integer instance associated with a particular
-// database key.
+// fetchInt64 retrieves an integer associated with a particular key.
 func (db *DB) fetchInt64(key []byte) int64 {
 	blob, err := db.lvl.Get(key, nil)
 	if err != nil {
@@ -154,18 +155,33 @@ func (db *DB) fetchInt64(key []byte) int64 {
 	return val
 }
 
-// storeInt64 update a specific database entry to the current time instance as a
-// unix timestamp.
+// storeInt64 stores an integer in the given key.
 func (db *DB) storeInt64(key []byte, n int64) error {
 	blob := make([]byte, binary.MaxVarintLen64)
 	blob = blob[:binary.PutVarint(blob, n)]
+	return db.lvl.Put(key, blob, nil)
+}
+
+// fetchUint64 retrieves an integer associated with a particular key.
+func (db *DB) fetchUint64(key []byte) uint64 {
+	blob, err := db.lvl.Get(key, nil)
+	if err != nil {
+		return 0
+	}
+	val, _ := binary.Uvarint(blob)
+	return val
+}
 
+// storeUint64 stores an integer in the given key.
+func (db *DB) storeUint64(key []byte, n uint64) error {
+	blob := make([]byte, binary.MaxVarintLen64)
+	blob = blob[:binary.PutUvarint(blob, n)]
 	return db.lvl.Put(key, blob, nil)
 }
 
 // Node retrieves a node with a given id from the database.
 func (db *DB) Node(id ID) *Node {
-	blob, err := db.lvl.Get(makeKey(id, nodeDBDiscoverRoot), nil)
+	blob, err := db.lvl.Get(makeKey(id, dbDiscoverRoot), nil)
 	if err != nil {
 		return nil
 	}
@@ -184,11 +200,31 @@ func mustDecodeNode(id, data []byte) *Node {
 
 // UpdateNode inserts - potentially overwriting - a node into the peer database.
 func (db *DB) UpdateNode(node *Node) error {
+	if node.Seq() < db.NodeSeq(node.ID()) {
+		return nil
+	}
 	blob, err := rlp.EncodeToBytes(&node.r)
 	if err != nil {
 		return err
 	}
-	return db.lvl.Put(makeKey(node.ID(), nodeDBDiscoverRoot), blob, nil)
+	if err := db.lvl.Put(makeKey(node.ID(), dbDiscoverRoot), blob, nil); err != nil {
+		return err
+	}
+	return db.storeUint64(makeKey(node.ID(), dbDiscoverSeq), node.Seq())
+}
+
+// NodeSeq returns the stored record sequence number of the given node.
+func (db *DB) NodeSeq(id ID) uint64 {
+	return db.fetchUint64(makeKey(id, dbDiscoverSeq))
+}
+
+// Resolve returns the stored record of the node if it has a larger sequence
+// number than n.
+func (db *DB) Resolve(n *Node) *Node {
+	if n.Seq() > db.NodeSeq(n.ID()) {
+		return n
+	}
+	return db.Node(n.ID())
 }
 
 // DeleteNode deletes all information/keys associated with a node.
@@ -218,7 +254,7 @@ func (db *DB) ensureExpirer() {
 // expirer should be started in a go routine, and is responsible for looping ad
 // infinitum and dropping stale data from the database.
 func (db *DB) expirer() {
-	tick := time.NewTicker(nodeDBCleanupCycle)
+	tick := time.NewTicker(dbCleanupCycle)
 	defer tick.Stop()
 	for {
 		select {
@@ -235,7 +271,7 @@ func (db *DB) expirer() {
 // expireNodes iterates over the database and deletes all nodes that have not
 // been seen (i.e. received a pong from) for some allotted time.
 func (db *DB) expireNodes() error {
-	threshold := time.Now().Add(-nodeDBNodeExpiration)
+	threshold := time.Now().Add(-dbNodeExpiration)
 
 	// Find discovered nodes that are older than the allowance
 	it := db.lvl.NewIterator(nil, nil)
@@ -244,7 +280,7 @@ func (db *DB) expireNodes() error {
 	for it.Next() {
 		// Skip the item if not a discovery node
 		id, field := splitKey(it.Key())
-		if field != nodeDBDiscoverRoot {
+		if field != dbDiscoverRoot {
 			continue
 		}
 		// Skip the node if not expired yet (and not self)
@@ -260,34 +296,44 @@ func (db *DB) expireNodes() error {
 // LastPingReceived retrieves the time of the last ping packet received from
 // a remote node.
 func (db *DB) LastPingReceived(id ID) time.Time {
-	return time.Unix(db.fetchInt64(makeKey(id, nodeDBDiscoverPing)), 0)
+	return time.Unix(db.fetchInt64(makeKey(id, dbDiscoverPing)), 0)
 }
 
 // UpdateLastPingReceived updates the last time we tried contacting a remote node.
 func (db *DB) UpdateLastPingReceived(id ID, instance time.Time) error {
-	return db.storeInt64(makeKey(id, nodeDBDiscoverPing), instance.Unix())
+	return db.storeInt64(makeKey(id, dbDiscoverPing), instance.Unix())
 }
 
 // LastPongReceived retrieves the time of the last successful pong from remote node.
 func (db *DB) LastPongReceived(id ID) time.Time {
 	// Launch expirer
 	db.ensureExpirer()
-	return time.Unix(db.fetchInt64(makeKey(id, nodeDBDiscoverPong)), 0)
+	return time.Unix(db.fetchInt64(makeKey(id, dbDiscoverPong)), 0)
 }
 
 // UpdateLastPongReceived updates the last pong time of a node.
 func (db *DB) UpdateLastPongReceived(id ID, instance time.Time) error {
-	return db.storeInt64(makeKey(id, nodeDBDiscoverPong), instance.Unix())
+	return db.storeInt64(makeKey(id, dbDiscoverPong), instance.Unix())
 }
 
 // FindFails retrieves the number of findnode failures since bonding.
 func (db *DB) FindFails(id ID) int {
-	return int(db.fetchInt64(makeKey(id, nodeDBDiscoverFindFails)))
+	return int(db.fetchInt64(makeKey(id, dbDiscoverFindFails)))
 }
 
 // UpdateFindFails updates the number of findnode failures since bonding.
 func (db *DB) UpdateFindFails(id ID, fails int) error {
-	return db.storeInt64(makeKey(id, nodeDBDiscoverFindFails), int64(fails))
+	return db.storeInt64(makeKey(id, dbDiscoverFindFails), int64(fails))
+}
+
+// LocalSeq retrieves the local record sequence counter.
+func (db *DB) localSeq(id ID) uint64 {
+	return db.fetchUint64(makeKey(id, dbLocalSeq))
+}
+
+// storeLocalSeq stores the local record sequence counter.
+func (db *DB) storeLocalSeq(id ID, n uint64) {
+	db.storeUint64(makeKey(id, dbLocalSeq), n)
 }
 
 // QuerySeeds retrieves random nodes to be used as potential seed nodes
@@ -309,7 +355,7 @@ seek:
 		ctr := id[0]
 		rand.Read(id[:])
 		id[0] = ctr + id[0]%16
-		it.Seek(makeKey(id, nodeDBDiscoverRoot))
+		it.Seek(makeKey(id, dbDiscoverRoot))
 
 		n := nextNode(it)
 		if n == nil {
@@ -334,7 +380,7 @@ seek:
 func nextNode(it iterator.Iterator) *Node {
 	for end := false; !end; end = !it.Next() {
 		id, field := splitKey(it.Key())
-		if field != nodeDBDiscoverRoot {
+		if field != dbDiscoverRoot {
 			continue
 		}
 		return mustDecodeNode(id[:], it.Value())
diff --git a/p2p/enode/nodedb_test.go b/p2p/enode/nodedb_test.go
index b476a3439..96794827c 100644
--- a/p2p/enode/nodedb_test.go
+++ b/p2p/enode/nodedb_test.go
@@ -332,7 +332,7 @@ var nodeDBExpirationNodes = []struct {
 			30303,
 			30303,
 		),
-		pong: time.Now().Add(-nodeDBNodeExpiration + time.Minute),
+		pong: time.Now().Add(-dbNodeExpiration + time.Minute),
 		exp:  false,
 	}, {
 		node: NewV4(
@@ -341,7 +341,7 @@ var nodeDBExpirationNodes = []struct {
 			30303,
 			30303,
 		),
-		pong: time.Now().Add(-nodeDBNodeExpiration - time.Minute),
+		pong: time.Now().Add(-dbNodeExpiration - time.Minute),
 		exp:  true,
 	},
 }
diff --git a/p2p/enr/enr.go b/p2p/enr/enr.go
index 251caf458..444820c15 100644
--- a/p2p/enr/enr.go
+++ b/p2p/enr/enr.go
@@ -156,7 +156,7 @@ func (r *Record) Set(e Entry) {
 }
 
 func (r *Record) invalidate() {
-	if r.signature == nil {
+	if r.signature != nil {
 		r.seq++
 	}
 	r.signature = nil
diff --git a/p2p/enr/enr_test.go b/p2p/enr/enr_test.go
index 9bf22478d..449c898a8 100644
--- a/p2p/enr/enr_test.go
+++ b/p2p/enr/enr_test.go
@@ -169,6 +169,18 @@ func TestDirty(t *testing.T) {
 	}
 }
 
+func TestSeq(t *testing.T) {
+	var r Record
+
+	assert.Equal(t, uint64(0), r.Seq())
+	r.Set(UDP(1))
+	assert.Equal(t, uint64(0), r.Seq())
+	signTest([]byte{5}, &r)
+	assert.Equal(t, uint64(0), r.Seq())
+	r.Set(UDP(2))
+	assert.Equal(t, uint64(1), r.Seq())
+}
+
 // TestGetSetOverwrite tests value overwrite when setting a new value with an existing key in record.
 func TestGetSetOverwrite(t *testing.T) {
 	var r Record
diff --git a/p2p/nat/nat.go b/p2p/nat/nat.go
index a254648c6..8fad921c4 100644
--- a/p2p/nat/nat.go
+++ b/p2p/nat/nat.go
@@ -129,21 +129,15 @@ func Map(m Interface, c chan struct{}, protocol string, extport, intport int, na
 // ExtIP assumes that the local machine is reachable on the given
 // external IP address, and that any required ports were mapped manually.
 // Mapping operations will not return an error but won't actually do anything.
-func ExtIP(ip net.IP) Interface {
-	if ip == nil {
-		panic("IP must not be nil")
-	}
-	return extIP(ip)
-}
+type ExtIP net.IP
 
-type extIP net.IP
-
-func (n extIP) ExternalIP() (net.IP, error) { return net.IP(n), nil }
-func (n extIP) String() string              { return fmt.Sprintf("ExtIP(%v)", net.IP(n)) }
+func (n ExtIP) ExternalIP() (net.IP, error) { return net.IP(n), nil }
+func (n ExtIP) String() string              { return fmt.Sprintf("ExtIP(%v)", net.IP(n)) }
 
 // These do nothing.
-func (extIP) AddMapping(string, int, int, string, time.Duration) error { return nil }
-func (extIP) DeleteMapping(string, int, int) error                     { return nil }
+
+func (ExtIP) AddMapping(string, int, int, string, time.Duration) error { return nil }
+func (ExtIP) DeleteMapping(string, int, int) error                     { return nil }
 
 // Any returns a port mapper that tries to discover any supported
 // mechanism on the local network.
diff --git a/p2p/nat/nat_test.go b/p2p/nat/nat_test.go
index 469101e99..814e6d9e1 100644
--- a/p2p/nat/nat_test.go
+++ b/p2p/nat/nat_test.go
@@ -28,7 +28,7 @@ import (
 func TestAutoDiscRace(t *testing.T) {
 	ad := startautodisc("thing", func() Interface {
 		time.Sleep(500 * time.Millisecond)
-		return extIP{33, 44, 55, 66}
+		return ExtIP{33, 44, 55, 66}
 	})
 
 	// Spawn a few concurrent calls to ad.ExternalIP.
diff --git a/p2p/netutil/iptrack.go b/p2p/netutil/iptrack.go
new file mode 100644
index 000000000..b9cbd5e1c
--- /dev/null
+++ b/p2p/netutil/iptrack.go
@@ -0,0 +1,130 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package netutil
+
+import (
+	"time"
+
+	"github.com/ethereum/go-ethereum/common/mclock"
+)
+
+// IPTracker predicts the external endpoint, i.e. IP address and port, of the local host
+// based on statements made by other hosts.
+type IPTracker struct {
+	window          time.Duration
+	contactWindow   time.Duration
+	minStatements   int
+	clock           mclock.Clock
+	statements      map[string]ipStatement
+	contact         map[string]mclock.AbsTime
+	lastStatementGC mclock.AbsTime
+	lastContactGC   mclock.AbsTime
+}
+
+type ipStatement struct {
+	endpoint string
+	time     mclock.AbsTime
+}
+
+// NewIPTracker creates an IP tracker.
+//
+// The window parameters configure the amount of past network events which are kept. The
+// minStatements parameter enforces a minimum number of statements which must be recorded
+// before any prediction is made. Higher values for these parameters decrease 'flapping' of
+// predictions as network conditions change. Window duration values should typically be in
+// the range of minutes.
+func NewIPTracker(window, contactWindow time.Duration, minStatements int) *IPTracker {
+	return &IPTracker{
+		window:        window,
+		contactWindow: contactWindow,
+		statements:    make(map[string]ipStatement),
+		minStatements: minStatements,
+		contact:       make(map[string]mclock.AbsTime),
+		clock:         mclock.System{},
+	}
+}
+
+// PredictFullConeNAT checks whether the local host is behind full cone NAT. It predicts by
+// checking whether any statement has been received from a node we didn't contact before
+// the statement was made.
+func (it *IPTracker) PredictFullConeNAT() bool {
+	now := it.clock.Now()
+	it.gcContact(now)
+	it.gcStatements(now)
+	for host, st := range it.statements {
+		if c, ok := it.contact[host]; !ok || c > st.time {
+			return true
+		}
+	}
+	return false
+}
+
+// PredictEndpoint returns the current prediction of the external endpoint.
+func (it *IPTracker) PredictEndpoint() string {
+	it.gcStatements(it.clock.Now())
+
+	// The current strategy is simple: find the endpoint with most statements.
+	counts := make(map[string]int)
+	maxcount, max := 0, ""
+	for _, s := range it.statements {
+		c := counts[s.endpoint] + 1
+		counts[s.endpoint] = c
+		if c > maxcount && c >= it.minStatements {
+			maxcount, max = c, s.endpoint
+		}
+	}
+	return max
+}
+
+// AddStatement records that a certain host thinks our external endpoint is the one given.
+func (it *IPTracker) AddStatement(host, endpoint string) {
+	now := it.clock.Now()
+	it.statements[host] = ipStatement{endpoint, now}
+	if time.Duration(now-it.lastStatementGC) >= it.window {
+		it.gcStatements(now)
+	}
+}
+
+// AddContact records that a packet containing our endpoint information has been sent to a
+// certain host.
+func (it *IPTracker) AddContact(host string) {
+	now := it.clock.Now()
+	it.contact[host] = now
+	if time.Duration(now-it.lastContactGC) >= it.contactWindow {
+		it.gcContact(now)
+	}
+}
+
+func (it *IPTracker) gcStatements(now mclock.AbsTime) {
+	it.lastStatementGC = now
+	cutoff := now.Add(-it.window)
+	for host, s := range it.statements {
+		if s.time < cutoff {
+			delete(it.statements, host)
+		}
+	}
+}
+
+func (it *IPTracker) gcContact(now mclock.AbsTime) {
+	it.lastContactGC = now
+	cutoff := now.Add(-it.contactWindow)
+	for host, ct := range it.contact {
+		if ct < cutoff {
+			delete(it.contact, host)
+		}
+	}
+}
diff --git a/p2p/netutil/iptrack_test.go b/p2p/netutil/iptrack_test.go
new file mode 100644
index 000000000..a9a2998a6
--- /dev/null
+++ b/p2p/netutil/iptrack_test.go
@@ -0,0 +1,138 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package netutil
+
+import (
+	"fmt"
+	mrand "math/rand"
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common/mclock"
+)
+
+const (
+	opStatement = iota
+	opContact
+	opPredict
+	opCheckFullCone
+)
+
+type iptrackTestEvent struct {
+	op       int
+	time     int // absolute, in milliseconds
+	ip, from string
+}
+
+func TestIPTracker(t *testing.T) {
+	tests := map[string][]iptrackTestEvent{
+		"minStatements": {
+			{opPredict, 0, "", ""},
+			{opStatement, 0, "127.0.0.1", "127.0.0.2"},
+			{opPredict, 1000, "", ""},
+			{opStatement, 1000, "127.0.0.1", "127.0.0.3"},
+			{opPredict, 1000, "", ""},
+			{opStatement, 1000, "127.0.0.1", "127.0.0.4"},
+			{opPredict, 1000, "127.0.0.1", ""},
+		},
+		"window": {
+			{opStatement, 0, "127.0.0.1", "127.0.0.2"},
+			{opStatement, 2000, "127.0.0.1", "127.0.0.3"},
+			{opStatement, 3000, "127.0.0.1", "127.0.0.4"},
+			{opPredict, 10000, "127.0.0.1", ""},
+			{opPredict, 10001, "", ""}, // first statement expired
+			{opStatement, 10100, "127.0.0.1", "127.0.0.2"},
+			{opPredict, 10200, "127.0.0.1", ""},
+		},
+		"fullcone": {
+			{opContact, 0, "", "127.0.0.2"},
+			{opStatement, 10, "127.0.0.1", "127.0.0.2"},
+			{opContact, 2000, "", "127.0.0.3"},
+			{opStatement, 2010, "127.0.0.1", "127.0.0.3"},
+			{opContact, 3000, "", "127.0.0.4"},
+			{opStatement, 3010, "127.0.0.1", "127.0.0.4"},
+			{opCheckFullCone, 3500, "false", ""},
+		},
+		"fullcone_2": {
+			{opContact, 0, "", "127.0.0.2"},
+			{opStatement, 10, "127.0.0.1", "127.0.0.2"},
+			{opContact, 2000, "", "127.0.0.3"},
+			{opStatement, 2010, "127.0.0.1", "127.0.0.3"},
+			{opStatement, 3000, "127.0.0.1", "127.0.0.4"},
+			{opContact, 3010, "", "127.0.0.4"},
+			{opCheckFullCone, 3500, "true", ""},
+		},
+	}
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) { runIPTrackerTest(t, test) })
+	}
+}
+
+func runIPTrackerTest(t *testing.T, evs []iptrackTestEvent) {
+	var (
+		clock mclock.Simulated
+		it    = NewIPTracker(10*time.Second, 10*time.Second, 3)
+	)
+	it.clock = &clock
+	for i, ev := range evs {
+		evtime := time.Duration(ev.time) * time.Millisecond
+		clock.Run(evtime - time.Duration(clock.Now()))
+		switch ev.op {
+		case opStatement:
+			it.AddStatement(ev.from, ev.ip)
+		case opContact:
+			it.AddContact(ev.from)
+		case opPredict:
+			if pred := it.PredictEndpoint(); pred != ev.ip {
+				t.Errorf("op %d: wrong prediction %q, want %q", i, pred, ev.ip)
+			}
+		case opCheckFullCone:
+			pred := fmt.Sprintf("%t", it.PredictFullConeNAT())
+			if pred != ev.ip {
+				t.Errorf("op %d: wrong prediction %s, want %s", i, pred, ev.ip)
+			}
+		}
+	}
+}
+
+// This checks that old statements and contacts are GCed even if Predict* isn't called.
+func TestIPTrackerForceGC(t *testing.T) {
+	var (
+		clock  mclock.Simulated
+		window = 10 * time.Second
+		rate   = 50 * time.Millisecond
+		max    = int(window/rate) + 1
+		it     = NewIPTracker(window, window, 3)
+	)
+	it.clock = &clock
+
+	for i := 0; i < 5*max; i++ {
+		e1 := make([]byte, 4)
+		e2 := make([]byte, 4)
+		mrand.Read(e1)
+		mrand.Read(e2)
+		it.AddStatement(string(e1), string(e2))
+		it.AddContact(string(e1))
+		clock.Run(rate)
+	}
+	if len(it.contact) > 2*max {
+		t.Errorf("contacts not GCed, have %d", len(it.contact))
+	}
+	if len(it.statements) > 2*max {
+		t.Errorf("statements not GCed, have %d", len(it.statements))
+	}
+}
diff --git a/p2p/protocol.go b/p2p/protocol.go
index 4b90a2a70..9438ab8e4 100644
--- a/p2p/protocol.go
+++ b/p2p/protocol.go
@@ -20,6 +20,7 @@ import (
 	"fmt"
 
 	"github.com/ethereum/go-ethereum/p2p/enode"
+	"github.com/ethereum/go-ethereum/p2p/enr"
 )
 
 // Protocol represents a P2P subprotocol implementation.
@@ -52,6 +53,9 @@ type Protocol struct {
 	// about a certain peer in the network. If an info retrieval function is set,
 	// but returns nil, it is assumed that the protocol handshake is still running.
 	PeerInfo func(id enode.ID) interface{}
+
+	// Attributes contains protocol specific information for the node record.
+	Attributes []enr.Entry
 }
 
 func (p Protocol) cap() Cap {
@@ -64,10 +68,6 @@ type Cap struct {
 	Version uint
 }
 
-func (cap Cap) RlpData() interface{} {
-	return []interface{}{cap.Name, cap.Version}
-}
-
 func (cap Cap) String() string {
 	return fmt.Sprintf("%s/%d", cap.Name, cap.Version)
 }
@@ -79,3 +79,5 @@ func (cs capsByNameAndVersion) Swap(i, j int) { cs[i], cs[j] = cs[j], cs[i] }
 func (cs capsByNameAndVersion) Less(i, j int) bool {
 	return cs[i].Name < cs[j].Name || (cs[i].Name == cs[j].Name && cs[i].Version < cs[j].Version)
 }
+
+func (capsByNameAndVersion) ENRKey() string { return "cap" }
diff --git a/p2p/server.go b/p2p/server.go
index 40db758e2..6482c0401 100644
--- a/p2p/server.go
+++ b/p2p/server.go
@@ -20,9 +20,11 @@ package p2p
 import (
 	"bytes"
 	"crypto/ecdsa"
+	"encoding/hex"
 	"errors"
 	"fmt"
 	"net"
+	"sort"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -35,8 +37,10 @@ import (
 	"github.com/ethereum/go-ethereum/p2p/discover"
 	"github.com/ethereum/go-ethereum/p2p/discv5"
 	"github.com/ethereum/go-ethereum/p2p/enode"
+	"github.com/ethereum/go-ethereum/p2p/enr"
 	"github.com/ethereum/go-ethereum/p2p/nat"
 	"github.com/ethereum/go-ethereum/p2p/netutil"
+	"github.com/ethereum/go-ethereum/rlp"
 )
 
 const (
@@ -160,6 +164,8 @@ type Server struct {
 	lock    sync.Mutex // protects running
 	running bool
 
+	nodedb       *enode.DB
+	localnode    *enode.LocalNode
 	ntab         discoverTable
 	listener     net.Listener
 	ourHandshake *protoHandshake
@@ -347,43 +353,13 @@ func (srv *Server) SubscribeEvents(ch chan *PeerEvent) event.Subscription {
 // Self returns the local node's endpoint information.
 func (srv *Server) Self() *enode.Node {
 	srv.lock.Lock()
-	running, listener, ntab := srv.running, srv.listener, srv.ntab
+	ln := srv.localnode
 	srv.lock.Unlock()
 
-	if !running {
+	if ln == nil {
 		return enode.NewV4(&srv.PrivateKey.PublicKey, net.ParseIP("0.0.0.0"), 0, 0)
 	}
-	return srv.makeSelf(listener, ntab)
-}
-
-func (srv *Server) makeSelf(listener net.Listener, ntab discoverTable) *enode.Node {
-	// If the node is running but discovery is off, manually assemble the node infos.
-	if ntab == nil {
-		addr := srv.tcpAddr(listener)
-		return enode.NewV4(&srv.PrivateKey.PublicKey, addr.IP, addr.Port, 0)
-	}
-	// Otherwise return the discovery node.
-	return ntab.Self()
-}
-
-func (srv *Server) tcpAddr(listener net.Listener) net.TCPAddr {
-	addr := net.TCPAddr{IP: net.IP{0, 0, 0, 0}}
-	if listener == nil {
-		return addr // Inbound connections disabled, use zero address.
-	}
-	// Otherwise inject the listener address too.
-	if a, ok := listener.Addr().(*net.TCPAddr); ok {
-		addr = *a
-	}
-	if srv.NAT != nil {
-		if ip, err := srv.NAT.ExternalIP(); err == nil {
-			addr.IP = ip
-		}
-	}
-	if addr.IP.IsUnspecified() {
-		addr.IP = net.IP{127, 0, 0, 1}
-	}
-	return addr
+	return ln.Node()
 }
 
 // Stop terminates the server and all active peer connections.
@@ -443,7 +419,9 @@ func (srv *Server) Start() (err error) {
 	if srv.log == nil {
 		srv.log = log.New()
 	}
-	srv.log.Info("Starting P2P networking")
+	if srv.NoDial && srv.ListenAddr == "" {
+		srv.log.Warn("P2P server will be useless, neither dialing nor listening")
+	}
 
 	// static fields
 	if srv.PrivateKey == nil {
@@ -466,65 +444,120 @@ func (srv *Server) Start() (err error) {
 	srv.peerOp = make(chan peerOpFunc)
 	srv.peerOpDone = make(chan struct{})
 
-	var (
-		conn      *net.UDPConn
-		sconn     *sharedUDPConn
-		realaddr  *net.UDPAddr
-		unhandled chan discover.ReadPacket
-	)
-
-	if !srv.NoDiscovery || srv.DiscoveryV5 {
-		addr, err := net.ResolveUDPAddr("udp", srv.ListenAddr)
-		if err != nil {
+	if err := srv.setupLocalNode(); err != nil {
+		return err
+	}
+	if srv.ListenAddr != "" {
+		if err := srv.setupListening(); err != nil {
 			return err
 		}
-		conn, err = net.ListenUDP("udp", addr)
-		if err != nil {
-			return err
+	}
+	if err := srv.setupDiscovery(); err != nil {
+		return err
+	}
+
+	dynPeers := srv.maxDialedConns()
+	dialer := newDialState(srv.localnode.ID(), srv.StaticNodes, srv.BootstrapNodes, srv.ntab, dynPeers, srv.NetRestrict)
+	srv.loopWG.Add(1)
+	go srv.run(dialer)
+	return nil
+}
+
+func (srv *Server) setupLocalNode() error {
+	// Create the devp2p handshake.
+	pubkey := crypto.FromECDSAPub(&srv.PrivateKey.PublicKey)
+	srv.ourHandshake = &protoHandshake{Version: baseProtocolVersion, Name: srv.Name, ID: pubkey[1:]}
+	for _, p := range srv.Protocols {
+		srv.ourHandshake.Caps = append(srv.ourHandshake.Caps, p.cap())
+	}
+	sort.Sort(capsByNameAndVersion(srv.ourHandshake.Caps))
+
+	// Create the local node.
+	db, err := enode.OpenDB(srv.Config.NodeDatabase)
+	if err != nil {
+		return err
+	}
+	srv.nodedb = db
+	srv.localnode = enode.NewLocalNode(db, srv.PrivateKey)
+	srv.localnode.SetFallbackIP(net.IP{127, 0, 0, 1})
+	srv.localnode.Set(capsByNameAndVersion(srv.ourHandshake.Caps))
+	// TODO: check conflicts
+	for _, p := range srv.Protocols {
+		for _, e := range p.Attributes {
+			srv.localnode.Set(e)
 		}
-		realaddr = conn.LocalAddr().(*net.UDPAddr)
-		if srv.NAT != nil {
-			if !realaddr.IP.IsLoopback() {
-				go nat.Map(srv.NAT, srv.quit, "udp", realaddr.Port, realaddr.Port, "ethereum discovery")
-			}
-			// TODO: react to external IP changes over time.
-			if ext, err := srv.NAT.ExternalIP(); err == nil {
-				realaddr = &net.UDPAddr{IP: ext, Port: realaddr.Port}
+	}
+	switch srv.NAT.(type) {
+	case nil:
+		// No NAT interface, do nothing.
+	case nat.ExtIP:
+		// ExtIP doesn't block, set the IP right away.
+		ip, _ := srv.NAT.ExternalIP()
+		srv.localnode.SetStaticIP(ip)
+	default:
+		// Ask the router about the IP. This takes a while and blocks startup,
+		// do it in the background.
+		srv.loopWG.Add(1)
+		go func() {
+			defer srv.loopWG.Done()
+			if ip, err := srv.NAT.ExternalIP(); err == nil {
+				srv.localnode.SetStaticIP(ip)
 			}
-		}
+		}()
+	}
+	return nil
+}
+
+func (srv *Server) setupDiscovery() error {
+	if srv.NoDiscovery && !srv.DiscoveryV5 {
+		return nil
 	}
 
-	if !srv.NoDiscovery && srv.DiscoveryV5 {
-		unhandled = make(chan discover.ReadPacket, 100)
-		sconn = &sharedUDPConn{conn, unhandled}
+	addr, err := net.ResolveUDPAddr("udp", srv.ListenAddr)
+	if err != nil {
+		return err
+	}
+	conn, err := net.ListenUDP("udp", addr)
+	if err != nil {
+		return err
+	}
+	realaddr := conn.LocalAddr().(*net.UDPAddr)
+	srv.log.Debug("UDP listener up", "addr", realaddr)
+	if srv.NAT != nil {
+		if !realaddr.IP.IsLoopback() {
+			go nat.Map(srv.NAT, srv.quit, "udp", realaddr.Port, realaddr.Port, "ethereum discovery")
+		}
 	}
+	srv.localnode.SetFallbackUDP(realaddr.Port)
 
-	// node table
+	// Discovery V4
+	var unhandled chan discover.ReadPacket
+	var sconn *sharedUDPConn
 	if !srv.NoDiscovery {
+		if srv.DiscoveryV5 {
+			unhandled = make(chan discover.ReadPacket, 100)
+			sconn = &sharedUDPConn{conn, unhandled}
+		}
 		cfg := discover.Config{
-			PrivateKey:   srv.PrivateKey,
-			AnnounceAddr: realaddr,
-			NodeDBPath:   srv.NodeDatabase,
-			NetRestrict:  srv.NetRestrict,
-			Bootnodes:    srv.BootstrapNodes,
-			Unhandled:    unhandled,
+			PrivateKey:  srv.PrivateKey,
+			NetRestrict: srv.NetRestrict,
+			Bootnodes:   srv.BootstrapNodes,
+			Unhandled:   unhandled,
 		}
-		ntab, err := discover.ListenUDP(conn, cfg)
+		ntab, err := discover.ListenUDP(conn, srv.localnode, cfg)
 		if err != nil {
 			return err
 		}
 		srv.ntab = ntab
 	}
-
+	// Discovery V5
 	if srv.DiscoveryV5 {
-		var (
-			ntab *discv5.Network
-			err  error
-		)
+		var ntab *discv5.Network
+		var err error
 		if sconn != nil {
-			ntab, err = discv5.ListenUDP(srv.PrivateKey, sconn, realaddr, "", srv.NetRestrict) //srv.NodeDatabase)
+			ntab, err = discv5.ListenUDP(srv.PrivateKey, sconn, "", srv.NetRestrict)
 		} else {
-			ntab, err = discv5.ListenUDP(srv.PrivateKey, conn, realaddr, "", srv.NetRestrict) //srv.NodeDatabase)
+			ntab, err = discv5.ListenUDP(srv.PrivateKey, conn, "", srv.NetRestrict)
 		}
 		if err != nil {
 			return err
@@ -534,32 +567,10 @@ func (srv *Server) Start() (err error) {
 		}
 		srv.DiscV5 = ntab
 	}
-
-	dynPeers := srv.maxDialedConns()
-	dialer := newDialState(srv.StaticNodes, srv.BootstrapNodes, srv.ntab, dynPeers, srv.NetRestrict)
-
-	// handshake
-	pubkey := crypto.FromECDSAPub(&srv.PrivateKey.PublicKey)
-	srv.ourHandshake = &protoHandshake{Version: baseProtocolVersion, Name: srv.Name, ID: pubkey[1:]}
-	for _, p := range srv.Protocols {
-		srv.ourHandshake.Caps = append(srv.ourHandshake.Caps, p.cap())
-	}
-	// listen/dial
-	if srv.ListenAddr != "" {
-		if err := srv.startListening(); err != nil {
-			return err
-		}
-	}
-	if srv.NoDial && srv.ListenAddr == "" {
-		srv.log.Warn("P2P server will be useless, neither dialing nor listening")
-	}
-
-	srv.loopWG.Add(1)
-	go srv.run(dialer)
 	return nil
 }
 
-func (srv *Server) startListening() error {
+func (srv *Server) setupListening() error {
 	// Launch the TCP listener.
 	listener, err := net.Listen("tcp", srv.ListenAddr)
 	if err != nil {
@@ -568,8 +579,11 @@ func (srv *Server) startListening() error {
 	laddr := listener.Addr().(*net.TCPAddr)
 	srv.ListenAddr = laddr.String()
 	srv.listener = listener
+	srv.localnode.Set(enr.TCP(laddr.Port))
+
 	srv.loopWG.Add(1)
 	go srv.listenLoop()
+
 	// Map the TCP listening port if NAT is configured.
 	if !laddr.IP.IsLoopback() && srv.NAT != nil {
 		srv.loopWG.Add(1)
@@ -589,7 +603,10 @@ type dialer interface {
 }
 
 func (srv *Server) run(dialstate dialer) {
+	srv.log.Info("Started P2P networking", "self", srv.localnode.Node())
 	defer srv.loopWG.Done()
+	defer srv.nodedb.Close()
+
 	var (
 		peers        = make(map[enode.ID]*Peer)
 		inboundCount = 0
@@ -781,7 +798,7 @@ func (srv *Server) encHandshakeChecks(peers map[enode.ID]*Peer, inboundCount int
 		return DiscTooManyPeers
 	case peers[c.node.ID()] != nil:
 		return DiscAlreadyConnected
-	case c.node.ID() == srv.Self().ID():
+	case c.node.ID() == srv.localnode.ID():
 		return DiscSelf
 	default:
 		return nil
@@ -802,15 +819,11 @@ func (srv *Server) maxDialedConns() int {
 	return srv.MaxPeers / r
 }
 
-type tempError interface {
-	Temporary() bool
-}
-
 // listenLoop runs in its own goroutine and accepts
 // inbound connections.
 func (srv *Server) listenLoop() {
 	defer srv.loopWG.Done()
-	srv.log.Info("RLPx listener up", "self", srv.Self())
+	srv.log.Debug("TCP listener up", "addr", srv.listener.Addr())
 
 	tokens := defaultMaxPendingPeers
 	if srv.MaxPendingPeers > 0 {
@@ -831,7 +844,7 @@ func (srv *Server) listenLoop() {
 		)
 		for {
 			fd, err = srv.listener.Accept()
-			if tempErr, ok := err.(tempError); ok && tempErr.Temporary() {
+			if netutil.IsTemporaryError(err) {
 				srv.log.Debug("Temporary read error", "err", err)
 				continue
 			} else if err != nil {
@@ -864,10 +877,6 @@ func (srv *Server) listenLoop() {
 // as a peer. It returns when the connection has been added as a peer
 // or the handshakes have failed.
 func (srv *Server) SetupConn(fd net.Conn, flags connFlag, dialDest *enode.Node) error {
-	self := srv.Self()
-	if self == nil {
-		return errors.New("shutdown")
-	}
 	c := &conn{fd: fd, transport: srv.newTransport(fd), flags: flags, cont: make(chan error)}
 	err := srv.setupConn(c, flags, dialDest)
 	if err != nil {
@@ -1003,6 +1012,7 @@ type NodeInfo struct {
 	ID    string `json:"id"`    // Unique node identifier (also the encryption key)
 	Name  string `json:"name"`  // Name of the node, including client type, version, OS, custom data
 	Enode string `json:"enode"` // Enode URL for adding this peer from remote peers
+	ENR   string `json:"enr"`   // Ethereum Node Record
 	IP    string `json:"ip"`    // IP address of the node
 	Ports struct {
 		Discovery int `json:"discovery"` // UDP listening port for discovery protocol
@@ -1014,9 +1024,8 @@ type NodeInfo struct {
 
 // NodeInfo gathers and returns a collection of metadata known about the host.
 func (srv *Server) NodeInfo() *NodeInfo {
-	node := srv.Self()
-
 	// Gather and assemble the generic node infos
+	node := srv.Self()
 	info := &NodeInfo{
 		Name:       srv.Name,
 		Enode:      node.String(),
@@ -1027,6 +1036,9 @@ func (srv *Server) NodeInfo() *NodeInfo {
 	}
 	info.Ports.Discovery = node.UDP()
 	info.Ports.Listener = node.TCP()
+	if enc, err := rlp.EncodeToBytes(node.Record()); err == nil {
+		info.ENR = "0x" + hex.EncodeToString(enc)
+	}
 
 	// Gather all the running protocol infos (only once per protocol type)
 	for _, proto := range srv.Protocols {
diff --git a/p2p/server_test.go b/p2p/server_test.go
index e0b1fc122..7e11577d6 100644
--- a/p2p/server_test.go
+++ b/p2p/server_test.go
@@ -225,12 +225,15 @@ func TestServerTaskScheduling(t *testing.T) {
 
 	// The Server in this test isn't actually running
 	// because we're only interested in what run does.
+	db, _ := enode.OpenDB("")
 	srv := &Server{
-		Config:  Config{MaxPeers: 10},
-		quit:    make(chan struct{}),
-		ntab:    fakeTable{},
-		running: true,
-		log:     log.New(),
+		Config:    Config{MaxPeers: 10},
+		localnode: enode.NewLocalNode(db, newkey()),
+		nodedb:    db,
+		quit:      make(chan struct{}),
+		ntab:      fakeTable{},
+		running:   true,
+		log:       log.New(),
 	}
 	srv.loopWG.Add(1)
 	go func() {
@@ -271,11 +274,14 @@ func TestServerManyTasks(t *testing.T) {
 	}
 
 	var (
-		srv = &Server{
-			quit:    make(chan struct{}),
-			ntab:    fakeTable{},
-			running: true,
-			log:     log.New(),
+		db, _ = enode.OpenDB("")
+		srv   = &Server{
+			quit:      make(chan struct{}),
+			localnode: enode.NewLocalNode(db, newkey()),
+			nodedb:    db,
+			ntab:      fakeTable{},
+			running:   true,
+			log:       log.New(),
 		}
 		done       = make(chan *testTask)
 		start, end = 0, 0