Merge pull request #791 from fjl/discover-sha3-distance

p2p/discover: sha3-based node distance

14 files changed, 651 insertions, 292 deletions

diff --git a/common/types.go b/common/types.go
index daefcde11..183d48fb3 100644
--- a/common/types.go
+++ b/common/types.go
@@ -1,6 +1,10 @@
 package common
 
-import "math/big"
+import (
+	"math/big"
+	"math/rand"
+	"reflect"
+)
 
 const (
 	hashLength    = 32
@@ -48,6 +52,15 @@ func (h *Hash) Set(other Hash) {
 	}
 }
 
+// Generate implements testing/quick.Generator.
+func (h Hash) Generate(rand *rand.Rand, size int) reflect.Value {
+	m := rand.Intn(len(h))
+	for i := len(h) - 1; i > m; i-- {
+		h[i] = byte(rand.Uint32())
+	}
+	return reflect.ValueOf(h)
+}
+
 /////////// Address
 func BytesToAddress(b []byte) Address {
 	var a Address
diff --git a/eth/backend.go b/eth/backend.go
index 5acef2ded..21ee1247b 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -277,8 +277,8 @@ func (s *Ethereum) NodeInfo() *NodeInfo {
 		NodeUrl:    node.String(),
 		NodeID:     node.ID.String(),
 		IP:         node.IP.String(),
-		DiscPort:   node.DiscPort,
-		TCPPort:    node.TCPPort,
+		DiscPort:   int(node.UDP),
+		TCPPort:    int(node.TCP),
 		ListenAddr: s.net.ListenAddr,
 		Td:         s.ChainManager().Td().String(),
 	}
diff --git a/p2p/discover/database.go b/p2p/discover/database.go
index 964f86b84..dc0b97ddf 100644
--- a/p2p/discover/database.go
+++ b/p2p/discover/database.go
@@ -10,6 +10,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/logger/glog"
 	"github.com/ethereum/go-ethereum/rlp"
@@ -167,6 +168,7 @@ func (db *nodeDB) node(id NodeID) *Node {
 		glog.V(logger.Warn).Infof("failed to decode node RLP: %v", err)
 		return nil
 	}
+	node.sha = crypto.Sha3Hash(node.ID[:])
 	return node
 }
 
diff --git a/p2p/discover/database_test.go b/p2p/discover/database_test.go
index f327cf73b..3ed84a099 100644
--- a/p2p/discover/database_test.go
+++ b/p2p/discover/database_test.go
@@ -6,6 +6,7 @@ import (
 	"net"
 	"os"
 	"path/filepath"
+	"reflect"
 	"testing"
 	"time"
 )
@@ -85,11 +86,12 @@ func TestNodeDBInt64(t *testing.T) {
 }
 
 func TestNodeDBFetchStore(t *testing.T) {
-	node := &Node{
-		ID:      MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
-		IP:      net.IP([]byte{192, 168, 0, 1}),
-		TCPPort: 30303,
-	}
+	node := newNode(
+		MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
+		net.IP{192, 168, 0, 1},
+		30303,
+		30303,
+	)
 	inst := time.Now()
 
 	db, _ := newNodeDB("", Version)
@@ -124,34 +126,40 @@ func TestNodeDBFetchStore(t *testing.T) {
 	}
 	if stored := db.node(node.ID); stored == nil {
 		t.Errorf("node: not found")
-	} else if !bytes.Equal(stored.ID[:], node.ID[:]) || !stored.IP.Equal(node.IP) || stored.TCPPort != node.TCPPort {
+	} else if !reflect.DeepEqual(stored, node) {
 		t.Errorf("node: data mismatch: have %v, want %v", stored, node)
 	}
 }
 
 var nodeDBSeedQueryNodes = []struct {
-	node Node
+	node *Node
 	pong time.Time
 }{
 	{
-		node: Node{
-			ID: MustHexID("0x01d9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
-			IP: []byte{127, 0, 0, 1},
-		},
+		node: newNode(
+			MustHexID("0x01d9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
+			net.IP{127, 0, 0, 1},
+			30303,
+			30303,
+		),
 		pong: time.Now().Add(-2 * time.Second),
 	},
 	{
-		node: Node{
-			ID: MustHexID("0x02d9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
-			IP: []byte{127, 0, 0, 2},
-		},
+		node: newNode(
+			MustHexID("0x02d9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
+			net.IP{127, 0, 0, 2},
+			30303,
+			30303,
+		),
 		pong: time.Now().Add(-3 * time.Second),
 	},
 	{
-		node: Node{
-			ID: MustHexID("0x03d9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
-			IP: []byte{127, 0, 0, 3},
-		},
+		node: newNode(
+			MustHexID("0x03d9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
+			net.IP{127, 0, 0, 3},
+			30303,
+			30303,
+		),
 		pong: time.Now().Add(-1 * time.Second),
 	},
 }
@@ -162,7 +170,7 @@ func TestNodeDBSeedQuery(t *testing.T) {
 
 	// Insert a batch of nodes for querying
 	for i, seed := range nodeDBSeedQueryNodes {
-		if err := db.updateNode(&seed.node); err != nil {
+		if err := db.updateNode(seed.node); err != nil {
 			t.Fatalf("node %d: failed to insert: %v", i, err)
 		}
 	}
@@ -202,7 +210,7 @@ func TestNodeDBSeedQueryContinuation(t *testing.T) {
 
 	// Insert a batch of nodes for querying
 	for i, seed := range nodeDBSeedQueryNodes {
-		if err := db.updateNode(&seed.node); err != nil {
+		if err := db.updateNode(seed.node); err != nil {
 			t.Fatalf("node %d: failed to insert: %v", i, err)
 		}
 	}
@@ -266,22 +274,26 @@ func TestNodeDBPersistency(t *testing.T) {
 }
 
 var nodeDBExpirationNodes = []struct {
-	node Node
+	node *Node
 	pong time.Time
 	exp  bool
 }{
 	{
-		node: Node{
-			ID: MustHexID("0x01d9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
-			IP: []byte{127, 0, 0, 1},
-		},
+		node: newNode(
+			MustHexID("0x01d9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
+			net.IP{127, 0, 0, 1},
+			30303,
+			30303,
+		),
 		pong: time.Now().Add(-nodeDBNodeExpiration + time.Minute),
 		exp:  false,
 	}, {
-		node: Node{
-			ID: MustHexID("0x02d9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
-			IP: []byte{127, 0, 0, 2},
-		},
+		node: newNode(
+			MustHexID("0x02d9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
+			net.IP{127, 0, 0, 2},
+			30303,
+			30303,
+		),
 		pong: time.Now().Add(-nodeDBNodeExpiration - time.Minute),
 		exp:  true,
 	},
@@ -293,7 +305,7 @@ func TestNodeDBExpiration(t *testing.T) {
 
 	// Add all the test nodes and set their last pong time
 	for i, seed := range nodeDBExpirationNodes {
-		if err := db.updateNode(&seed.node); err != nil {
+		if err := db.updateNode(seed.node); err != nil {
 			t.Fatalf("node %d: failed to insert: %v", i, err)
 		}
 		if err := db.updateLastPong(seed.node.ID, seed.pong); err != nil {
diff --git a/p2p/discover/node.go b/p2p/discover/node.go
index e66ca37a4..a365ade15 100644
--- a/p2p/discover/node.go
+++ b/p2p/discover/node.go
@@ -6,7 +6,6 @@ import (
 	"encoding/hex"
 	"errors"
 	"fmt"
-	"io"
 	"math/big"
 	"math/rand"
 	"net"
@@ -14,51 +13,55 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/crypto/secp256k1"
-	"github.com/ethereum/go-ethereum/rlp"
 )
 
 const nodeIDBits = 512
 
 // Node represents a host on the network.
 type Node struct {
-	ID NodeID
-	IP net.IP
+	IP       net.IP // len 4 for IPv4 or 16 for IPv6
+	UDP, TCP uint16 // port numbers
+	ID       NodeID // the node's public key
 
-	DiscPort int // UDP listening port for discovery protocol
-	TCPPort  int // TCP listening port for RLPx
+	// This is a cached copy of sha3(ID) which is used for node
+	// distance calculations. This is part of Node in order to make it
+	// possible to write tests that need a node at a certain distance.
+	// In those tests, the content of sha will not actually correspond
+	// with ID.
+	sha common.Hash
 }
 
-func newNode(id NodeID, addr *net.UDPAddr) *Node {
+func newNode(id NodeID, ip net.IP, udpPort, tcpPort uint16) *Node {
+	if ipv4 := ip.To4(); ipv4 != nil {
+		ip = ipv4
+	}
 	return &Node{
-		ID:       id,
-		IP:       addr.IP,
-		DiscPort: addr.Port,
-		TCPPort:  addr.Port,
+		IP:  ip,
+		UDP: udpPort,
+		TCP: tcpPort,
+		ID:  id,
+		sha: crypto.Sha3Hash(id[:]),
 	}
 }
 
-func (n *Node) isValid() bool {
-	// TODO: don't accept localhost, LAN addresses from internet hosts
-	return !n.IP.IsMulticast() && !n.IP.IsUnspecified() && n.TCPPort != 0 && n.DiscPort != 0
-}
-
 func (n *Node) addr() *net.UDPAddr {
-	return &net.UDPAddr{IP: n.IP, Port: n.DiscPort}
+	return &net.UDPAddr{IP: n.IP, Port: int(n.UDP)}
 }
 
 // The string representation of a Node is a URL.
 // Please see ParseNode for a description of the format.
 func (n *Node) String() string {
-	addr := net.TCPAddr{IP: n.IP, Port: n.TCPPort}
+	addr := net.TCPAddr{IP: n.IP, Port: int(n.TCP)}
 	u := url.URL{
 		Scheme: "enode",
 		User:   url.User(fmt.Sprintf("%x", n.ID[:])),
 		Host:   addr.String(),
 	}
-	if n.DiscPort != n.TCPPort {
-		u.RawQuery = "discport=" + strconv.Itoa(n.DiscPort)
+	if n.UDP != n.TCP {
+		u.RawQuery = "discport=" + strconv.Itoa(int(n.UDP))
 	}
 	return u.String()
 }
@@ -80,36 +83,47 @@ func (n *Node) String() string {
 //
 //    enode://<hex node id>@10.3.58.6:30303?discport=30301
 func ParseNode(rawurl string) (*Node, error) {
-	var n Node
+	var (
+		id               NodeID
+		ip               net.IP
+		tcpPort, udpPort uint64
+	)
 	u, err := url.Parse(rawurl)
 	if u.Scheme != "enode" {
 		return nil, errors.New("invalid URL scheme, want \"enode\"")
 	}
+	// Parse the Node ID from the user portion.
 	if u.User == nil {
 		return nil, errors.New("does not contain node ID")
 	}
-	if n.ID, err = HexID(u.User.String()); err != nil {
+	if id, err = HexID(u.User.String()); err != nil {
 		return nil, fmt.Errorf("invalid node ID (%v)", err)
 	}
-	ip, port, err := net.SplitHostPort(u.Host)
+	// Parse the IP address.
+	host, port, err := net.SplitHostPort(u.Host)
 	if err != nil {
 		return nil, fmt.Errorf("invalid host: %v", err)
 	}
-	if n.IP = net.ParseIP(ip); n.IP == nil {
+	if ip = net.ParseIP(host); ip == nil {
 		return nil, errors.New("invalid IP address")
 	}
-	if n.TCPPort, err = strconv.Atoi(port); err != nil {
+	// Ensure the IP is 4 bytes long for IPv4 addresses.
+	if ipv4 := ip.To4(); ipv4 != nil {
+		ip = ipv4
+	}
+	// Parse the port numbers.
+	if tcpPort, err = strconv.ParseUint(port, 10, 16); err != nil {
 		return nil, errors.New("invalid port")
 	}
+	udpPort = tcpPort
 	qv := u.Query()
-	if qv.Get("discport") == "" {
-		n.DiscPort = n.TCPPort
-	} else {
-		if n.DiscPort, err = strconv.Atoi(qv.Get("discport")); err != nil {
+	if qv.Get("discport") != "" {
+		udpPort, err = strconv.ParseUint(qv.Get("discport"), 10, 16)
+		if err != nil {
 			return nil, errors.New("invalid discport in query")
 		}
 	}
-	return &n, nil
+	return newNode(id, ip, uint16(udpPort), uint16(tcpPort)), nil
 }
 
 // MustParseNode parses a node URL. It panics if the URL is not valid.
@@ -121,22 +135,6 @@ func MustParseNode(rawurl string) *Node {
 	return n
 }
 
-func (n Node) EncodeRLP(w io.Writer) error {
-	return rlp.Encode(w, rpcNode{IP: n.IP.String(), Port: uint16(n.TCPPort), ID: n.ID})
-}
-func (n *Node) DecodeRLP(s *rlp.Stream) (err error) {
-	var ext rpcNode
-	if err = s.Decode(&ext); err == nil {
-		n.TCPPort = int(ext.Port)
-		n.DiscPort = int(ext.Port)
-		n.ID = ext.ID
-		if n.IP = net.ParseIP(ext.IP); n.IP == nil {
-			return errors.New("invalid IP string")
-		}
-	}
-	return err
-}
-
 // NodeID is a unique identifier for each node.
 // The node identifier is a marshaled elliptic curve public key.
 type NodeID [nodeIDBits / 8]byte
@@ -221,7 +219,7 @@ func recoverNodeID(hash, sig []byte) (id NodeID, err error) {
 // distcmp compares the distances a->target and b->target.
 // Returns -1 if a is closer to target, 1 if b is closer to target
 // and 0 if they are equal.
-func distcmp(target, a, b NodeID) int {
+func distcmp(target, a, b common.Hash) int {
 	for i := range target {
 		da := a[i] ^ target[i]
 		db := b[i] ^ target[i]
@@ -271,7 +269,7 @@ var lzcount = [256]int{
 }
 
 // logdist returns the logarithmic distance between a and b, log2(a ^ b).
-func logdist(a, b NodeID) int {
+func logdist(a, b common.Hash) int {
 	lz := 0
 	for i := range a {
 		x := a[i] ^ b[i]
@@ -285,8 +283,8 @@ func logdist(a, b NodeID) int {
 	return len(a)*8 - lz
 }
 
-// randomID returns a random NodeID such that logdist(a, b) == n
-func randomID(a NodeID, n int) (b NodeID) {
+// hashAtDistance returns a random hash such that logdist(a, b) == n
+func hashAtDistance(a common.Hash, n int) (b common.Hash) {
 	if n == 0 {
 		return a
 	}
diff --git a/p2p/discover/node_test.go b/p2p/discover/node_test.go
index 60b01b6ca..b1babd989 100644
--- a/p2p/discover/node_test.go
+++ b/p2p/discover/node_test.go
@@ -9,6 +9,7 @@ import (
 	"testing/quick"
 	"time"
 
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
 )
 
@@ -48,46 +49,61 @@ var parseNodeTests = []struct {
 	},
 	{
 		rawurl: "enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@127.0.0.1:52150",
-		wantResult: &Node{
-			ID:       MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
-			IP:       net.ParseIP("127.0.0.1"),
-			DiscPort: 52150,
-			TCPPort:  52150,
-		},
+		wantResult: newNode(
+			MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
+			net.IP{0x7f, 0x0, 0x0, 0x1},
+			52150,
+			52150,
+		),
 	},
 	{
 		rawurl: "enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@[::]:52150",
-		wantResult: &Node{
-			ID:       MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
-			IP:       net.ParseIP("::"),
-			DiscPort: 52150,
-			TCPPort:  52150,
-		},
+		wantResult: newNode(
+			MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
+			net.ParseIP("::"),
+			52150,
+			52150,
+		),
 	},
 	{
-		rawurl: "enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@127.0.0.1:52150?discport=223344",
-		wantResult: &Node{
-			ID:       MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
-			IP:       net.ParseIP("127.0.0.1"),
-			DiscPort: 223344,
-			TCPPort:  52150,
-		},
+		rawurl: "enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@[2001:db8:3c4d:15::abcd:ef12]:52150",
+		wantResult: newNode(
+			MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
+			net.ParseIP("2001:db8:3c4d:15::abcd:ef12"),
+			52150,
+			52150,
+		),
+	},
+	{
+		rawurl: "enode://1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439@127.0.0.1:52150?discport=22334",
+		wantResult: newNode(
+			MustHexID("0x1dd9d65c4552b5eb43d5ad55a2ee3f56c6cbc1c64a5c8d659f51fcd51bace24351232b8d7821617d2b29b54b81cdefb9b3e9c37d7fd5f63270bcc9e1a6f6a439"),
+			net.IP{0x7f, 0x0, 0x0, 0x1},
+			22334,
+			52150,
+		),
 	},
 }
 
 func TestParseNode(t *testing.T) {
 	for i, test := range parseNodeTests {
 		n, err := ParseNode(test.rawurl)
-		if err == nil && test.wantError != "" {
-			t.Errorf("test %d: got nil error, expected %#q", i, test.wantError)
-			continue
-		}
-		if err != nil && err.Error() != test.wantError {
-			t.Errorf("test %d: got error %#q, expected %#q", i, err.Error(), test.wantError)
-			continue
-		}
-		if !reflect.DeepEqual(n, test.wantResult) {
-			t.Errorf("test %d: result mismatch:\ngot:  %#v, want: %#v", i, n, test.wantResult)
+		if test.wantError != "" {
+			if err == nil {
+				t.Errorf("test %d: got nil error, expected %#q", i, test.wantError)
+				continue
+			} else if err.Error() != test.wantError {
+				t.Errorf("test %d: got error %#q, expected %#q", i, err.Error(), test.wantError)
+				continue
+			}
+		} else {
+			if err != nil {
+				t.Errorf("test %d: unexpected error: %v", i, err)
+				continue
+			}
+			if !reflect.DeepEqual(n, test.wantResult) {
+				t.Errorf("test %d: result mismatch:\ngot:  %#v, want: %#v", i, n, test.wantResult)
+			}
 		}
 	}
 }
@@ -154,7 +170,7 @@ func TestNodeID_pubkeyBad(t *testing.T) {
 }
 
 func TestNodeID_distcmp(t *testing.T) {
-	distcmpBig := func(target, a, b NodeID) int {
+	distcmpBig := func(target, a, b common.Hash) int {
 		tbig := new(big.Int).SetBytes(target[:])
 		abig := new(big.Int).SetBytes(a[:])
 		bbig := new(big.Int).SetBytes(b[:])
@@ -167,15 +183,15 @@ func TestNodeID_distcmp(t *testing.T) {
 
 // the random tests is likely to miss the case where they're equal.
 func TestNodeID_distcmpEqual(t *testing.T) {
-	base := NodeID{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
-	x := NodeID{15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0}
+	base := common.Hash{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
+	x := common.Hash{15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0}
 	if distcmp(base, x, x) != 0 {
 		t.Errorf("distcmp(base, x, x) != 0")
 	}
 }
 
 func TestNodeID_logdist(t *testing.T) {
-	logdistBig := func(a, b NodeID) int {
+	logdistBig := func(a, b common.Hash) int {
 		abig, bbig := new(big.Int).SetBytes(a[:]), new(big.Int).SetBytes(b[:])
 		return new(big.Int).Xor(abig, bbig).BitLen()
 	}
@@ -186,19 +202,19 @@ func TestNodeID_logdist(t *testing.T) {
 
 // the random tests is likely to miss the case where they're equal.
 func TestNodeID_logdistEqual(t *testing.T) {
-	x := NodeID{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
+	x := common.Hash{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}
 	if logdist(x, x) != 0 {
 		t.Errorf("logdist(x, x) != 0")
 	}
 }
 
-func TestNodeID_randomID(t *testing.T) {
+func TestNodeID_hashAtDistance(t *testing.T) {
 	// we don't use quick.Check here because its output isn't
 	// very helpful when the test fails.
 	for i := 0; i < quickcfg.MaxCount; i++ {
-		a := gen(NodeID{}, quickrand).(NodeID)
-		dist := quickrand.Intn(len(NodeID{}) * 8)
-		result := randomID(a, dist)
+		a := gen(common.Hash{}, quickrand).(common.Hash)
+		dist := quickrand.Intn(len(common.Hash{}) * 8)
+		result := hashAtDistance(a, dist)
 		actualdist := logdist(result, a)
 
 		if dist != actualdist {
@@ -209,6 +225,9 @@ func TestNodeID_randomID(t *testing.T) {
 	}
 }
 
+// TODO: this can be dropped when we require Go >= 1.5
+// because testing/quick learned to generate arrays in 1.5.
+
 func (NodeID) Generate(rand *rand.Rand, size int) reflect.Value {
 	var id NodeID
 	m := rand.Intn(len(id))
diff --git a/p2p/discover/table.go b/p2p/discover/table.go
index d3fe373f4..2c9cb80d5 100644
--- a/p2p/discover/table.go
+++ b/p2p/discover/table.go
@@ -7,19 +7,24 @@
 package discover
 
 import (
+	"crypto/rand"
 	"net"
 	"sort"
 	"sync"
 	"time"
 
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/logger"
 	"github.com/ethereum/go-ethereum/logger/glog"
 )
 
 const (
-	alpha               = 3              // Kademlia concurrency factor
-	bucketSize          = 16             // Kademlia bucket size
-	nBuckets            = nodeIDBits + 1 // Number of buckets
+	alpha      = 3  // Kademlia concurrency factor
+	bucketSize = 16 // Kademlia bucket size
+	hashBits   = len(common.Hash{}) * 8
+	nBuckets   = hashBits + 1 // Number of buckets
+
 	maxBondingPingPongs = 10
 )
 
@@ -71,7 +76,7 @@ func newTable(t transport, ourID NodeID, ourAddr *net.UDPAddr, nodeDBPath string
 	tab := &Table{
 		net:       t,
 		db:        db,
-		self:      newNode(ourID, ourAddr),
+		self:      newNode(ourID, ourAddr.IP, uint16(ourAddr.Port), uint16(ourAddr.Port)),
 		bonding:   make(map[NodeID]*bondproc),
 		bondslots: make(chan struct{}, maxBondingPingPongs),
 	}
@@ -105,6 +110,7 @@ func (tab *Table) Bootstrap(nodes []*Node) {
 	tab.nursery = make([]*Node, 0, len(nodes))
 	for _, n := range nodes {
 		cpy := *n
+		cpy.sha = crypto.Sha3Hash(n.ID[:])
 		tab.nursery = append(tab.nursery, &cpy)
 	}
 	tab.mutex.Unlock()
@@ -114,21 +120,23 @@ func (tab *Table) Bootstrap(nodes []*Node) {
 // Lookup performs a network search for nodes close
 // to the given target. It approaches the target by querying
 // nodes that are closer to it on each iteration.
-func (tab *Table) Lookup(target NodeID) []*Node {
+// The given target does not need to be an actual node
+// identifier.
+func (tab *Table) Lookup(targetID NodeID) []*Node {
 	var (
+		target         = crypto.Sha3Hash(targetID[:])
 		asked          = make(map[NodeID]bool)
 		seen           = make(map[NodeID]bool)
 		reply          = make(chan []*Node, alpha)
 		pendingQueries = 0
 	)
-	// don't query further if we hit the target or ourself.
+	// don't query further if we hit ourself.
 	// unlikely to happen often in practice.
-	asked[target] = true
 	asked[tab.self.ID] = true
 
 	tab.mutex.Lock()
 	// update last lookup stamp (for refresh logic)
-	tab.buckets[logdist(tab.self.ID, target)].lastLookup = time.Now()
+	tab.buckets[logdist(tab.self.sha, target)].lastLookup = time.Now()
 	// generate initial result set
 	result := tab.closest(target, bucketSize)
 	tab.mutex.Unlock()
@@ -141,7 +149,7 @@ func (tab *Table) Lookup(target NodeID) []*Node {
 				asked[n.ID] = true
 				pendingQueries++
 				go func() {
-					r, _ := tab.net.findnode(n.ID, n.addr(), target)
+					r, _ := tab.net.findnode(n.ID, n.addr(), targetID)
 					reply <- tab.bondall(r)
 				}()
 			}
@@ -164,17 +172,16 @@ func (tab *Table) Lookup(target NodeID) []*Node {
 
 // refresh performs a lookup for a random target to keep buckets full.
 func (tab *Table) refresh() {
-	ld := -1 // logdist of chosen bucket
-	tab.mutex.Lock()
-	for i, b := range tab.buckets {
-		if i > 0 && b.lastLookup.Before(time.Now().Add(-1*time.Hour)) {
-			ld = i
-			break
-		}
-	}
-	tab.mutex.Unlock()
-
-	result := tab.Lookup(randomID(tab.self.ID, ld))
+	// The Kademlia paper specifies that the bucket refresh should
+	// perform a refresh in the least recently used bucket. We cannot
+	// adhere to this because the findnode target is a 512bit value
+	// (not hash-sized) and it is not easily possible to generate a
+	// sha3 preimage that falls into a chosen bucket.
+	//
+	// We perform a lookup with a random target instead.
+	var target NodeID
+	rand.Read(target[:])
+	result := tab.Lookup(target)
 	if len(result) == 0 {
 		// Pick a batch of previously know seeds to lookup with
 		seeds := tab.db.querySeeds(10)
@@ -194,7 +201,7 @@ func (tab *Table) refresh() {
 
 // closest returns the n nodes in the table that are closest to the
 // given id. The caller must hold tab.mutex.
-func (tab *Table) closest(target NodeID, nresults int) *nodesByDistance {
+func (tab *Table) closest(target common.Hash, nresults int) *nodesByDistance {
 	// This is a very wasteful way to find the closest nodes but
 	// obviously correct. I believe that tree-based buckets would make
 	// this easier to implement efficiently.
@@ -220,7 +227,7 @@ func (tab *Table) bondall(nodes []*Node) (result []*Node) {
 	rc := make(chan *Node, len(nodes))
 	for i := range nodes {
 		go func(n *Node) {
-			nn, _ := tab.bond(false, n.ID, n.addr(), uint16(n.TCPPort))
+			nn, _ := tab.bond(false, n.ID, n.addr(), uint16(n.TCP))
 			rc <- nn
 		}(nodes[i])
 	}
@@ -276,7 +283,8 @@ func (tab *Table) bond(pinged bool, id NodeID, addr *net.UDPAddr, tcpPort uint16
 	}
 	tab.mutex.Lock()
 	defer tab.mutex.Unlock()
-	if b := tab.buckets[logdist(tab.self.ID, n.ID)]; !b.bump(n) {
+	b := tab.buckets[logdist(tab.self.sha, n.sha)]
+	if !b.bump(n) {
 		tab.pingreplace(n, b)
 	}
 	return n, nil
@@ -299,12 +307,7 @@ func (tab *Table) pingpong(w *bondproc, pinged bool, id NodeID, addr *net.UDPAdd
 		tab.net.waitping(id)
 	}
 	// Bonding succeeded, update the node database
-	w.n = &Node{
-		ID:       id,
-		IP:       addr.IP,
-		DiscPort: addr.Port,
-		TCPPort:  int(tcpPort),
-	}
+	w.n = newNode(id, addr.IP, uint16(addr.Port), tcpPort)
 	tab.db.updateNode(w.n)
 	close(w.done)
 }
@@ -345,12 +348,11 @@ func (tab *Table) ping(id NodeID, addr *net.UDPAddr) error {
 func (tab *Table) add(entries []*Node) {
 outer:
 	for _, n := range entries {
-		if n == nil || n.ID == tab.self.ID {
-			// skip bad entries. The RLP decoder returns nil for empty
-			// input lists.
+		if n.ID == tab.self.ID {
+			// don't add self.
 			continue
 		}
-		bucket := tab.buckets[logdist(tab.self.ID, n.ID)]
+		bucket := tab.buckets[logdist(tab.self.sha, n.sha)]
 		for i := range bucket.entries {
 			if bucket.entries[i].ID == n.ID {
 				// already in bucket
@@ -379,13 +381,13 @@ func (b *bucket) bump(n *Node) bool {
 // distance to target.
 type nodesByDistance struct {
 	entries []*Node
-	target  NodeID
+	target  common.Hash
 }
 
 // push adds the given node to the list, keeping the total size below maxElems.
 func (h *nodesByDistance) push(n *Node, maxElems int) {
 	ix := sort.Search(len(h.entries), func(i int) bool {
-		return distcmp(h.target, h.entries[i].ID, n.ID) > 0
+		return distcmp(h.target, h.entries[i].sha, n.sha) > 0
 	})
 	if len(h.entries) < maxElems {
 		h.entries = append(h.entries, n)
diff --git a/p2p/discover/table_test.go b/p2p/discover/table_test.go
index e2bd3c8ad..aa5267928 100644
--- a/p2p/discover/table_test.go
+++ b/p2p/discover/table_test.go
@@ -4,11 +4,13 @@ import (
 	"crypto/ecdsa"
 	"fmt"
 	"math/rand"
+
 	"net"
 	"reflect"
 	"testing"
 	"testing/quick"
 
+	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
 )
 
@@ -16,17 +18,19 @@ func TestTable_pingReplace(t *testing.T) {
 	doit := func(newNodeIsResponding, lastInBucketIsResponding bool) {
 		transport := newPingRecorder()
 		tab := newTable(transport, NodeID{}, &net.UDPAddr{}, "")
-		last := fillBucket(tab, 200)
-		pingSender := randomID(tab.self.ID, 200)
+		pingSender := newNode(MustHexID("a502af0f59b2aab7746995408c79e9ca312d2793cc997e44fc55eda62f0150bbb8c59a6f9269ba3a081518b62699ee807c7c19c20125ddfccca872608af9e370"), net.IP{}, 99, 99)
+
+		// fill up the sender's bucket.
+		last := fillBucket(tab, 253)
 
-		// this gotPing should replace the last node
-		// if the last node is not responding.
+		// this call to bond should replace the last node
+		// in its bucket if the node is not responding.
 		transport.responding[last.ID] = lastInBucketIsResponding
-		transport.responding[pingSender] = newNodeIsResponding
-		tab.bond(true, pingSender, &net.UDPAddr{}, 0)
+		transport.responding[pingSender.ID] = newNodeIsResponding
+		tab.bond(true, pingSender.ID, &net.UDPAddr{}, 0)
 
 		// first ping goes to sender (bonding pingback)
-		if !transport.pinged[pingSender] {
+		if !transport.pinged[pingSender.ID] {
 			t.Error("table did not ping back sender")
 		}
 		if newNodeIsResponding {
@@ -39,22 +43,22 @@ func TestTable_pingReplace(t *testing.T) {
 
 		tab.mutex.Lock()
 		defer tab.mutex.Unlock()
-		if l := len(tab.buckets[200].entries); l != bucketSize {
-			t.Errorf("wrong bucket size after gotPing: got %d, want %d", bucketSize, l)
+		if l := len(tab.buckets[253].entries); l != bucketSize {
+			t.Errorf("wrong bucket size after bond: got %d, want %d", l, bucketSize)
 		}
 
 		if lastInBucketIsResponding || !newNodeIsResponding {
-			if !contains(tab.buckets[200].entries, last.ID) {
+			if !contains(tab.buckets[253].entries, last.ID) {
 				t.Error("last entry was removed")
 			}
-			if contains(tab.buckets[200].entries, pingSender) {
+			if contains(tab.buckets[253].entries, pingSender.ID) {
 				t.Error("new entry was added")
 			}
 		} else {
-			if contains(tab.buckets[200].entries, last.ID) {
+			if contains(tab.buckets[253].entries, last.ID) {
 				t.Error("last entry was not removed")
 			}
-			if !contains(tab.buckets[200].entries, pingSender) {
+			if !contains(tab.buckets[253].entries, pingSender.ID) {
 				t.Error("new entry was not added")
 			}
 		}
@@ -62,7 +66,7 @@ func TestTable_pingReplace(t *testing.T) {
 
 	doit(true, true)
 	doit(false, true)
-	doit(false, true)
+	doit(true, false)
 	doit(false, false)
 }
 
@@ -76,7 +80,7 @@ func TestBucket_bumpNoDuplicates(t *testing.T) {
 			n := rand.Intn(bucketSize-1) + 1
 			nodes := make([]*Node, n)
 			for i := range nodes {
-				nodes[i] = &Node{ID: randomID(NodeID{}, 200)}
+				nodes[i] = nodeAtDistance(common.Hash{}, 200)
 			}
 			args[0] = reflect.ValueOf(nodes)
 			// generate random bump positions.
@@ -108,14 +112,26 @@ func TestBucket_bumpNoDuplicates(t *testing.T) {
 	}
 }
 
+// fillBucket inserts nodes into the given bucket until
+// it is full. The node's IDs dont correspond to their
+// hashes.
 func fillBucket(tab *Table, ld int) (last *Node) {
 	b := tab.buckets[ld]
 	for len(b.entries) < bucketSize {
-		b.entries = append(b.entries, &Node{ID: randomID(tab.self.ID, ld)})
+		b.entries = append(b.entries, nodeAtDistance(tab.self.sha, ld))
 	}
 	return b.entries[bucketSize-1]
 }
 
+// nodeAtDistance creates a node for which logdist(base, n.sha) == ld.
+// The node's ID does not correspond to n.sha.
+func nodeAtDistance(base common.Hash, ld int) (n *Node) {
+	n = new(Node)
+	n.sha = hashAtDistance(base, ld)
+	copy(n.ID[:], n.sha[:]) // ensure the node still has a unique ID
+	return n
+}
+
 type pingRecorder struct{ responding, pinged map[NodeID]bool }
 
 func newPingRecorder() *pingRecorder {
@@ -177,8 +193,8 @@ func TestTable_closest(t *testing.T) {
 				if contains(result, n.ID) {
 					continue // don't run the check below for nodes in result
 				}
-				farthestResult := result[len(result)-1].ID
-				if distcmp(test.Target, n.ID, farthestResult) < 0 {
+				farthestResult := result[len(result)-1].sha
+				if distcmp(test.Target, n.sha, farthestResult) < 0 {
 					t.Errorf("table contains node that is closer to target but it's not in result")
 					t.Logf("  Target:          %v", test.Target)
 					t.Logf("  Farthest Result: %v", farthestResult)
@@ -196,7 +212,7 @@ func TestTable_closest(t *testing.T) {
 
 type closeTest struct {
 	Self   NodeID
-	Target NodeID
+	Target common.Hash
 	All    []*Node
 	N      int
 }
@@ -204,7 +220,7 @@ type closeTest struct {
 func (*closeTest) Generate(rand *rand.Rand, size int) reflect.Value {
 	t := &closeTest{
 		Self:   gen(NodeID{}, rand).(NodeID),
-		Target: gen(NodeID{}, rand).(NodeID),
+		Target: gen(common.Hash{}, rand).(common.Hash),
 		N:      rand.Intn(bucketSize),
 	}
 	for _, id := range gen([]NodeID{}, rand).([]NodeID) {
@@ -214,22 +230,21 @@ func (*closeTest) Generate(rand *rand.Rand, size int) reflect.Value {
 }
 
 func TestTable_Lookup(t *testing.T) {
-	self := gen(NodeID{}, quickrand).(NodeID)
-	target := randomID(self, 200)
-	transport := findnodeOracle{t, target}
-	tab := newTable(transport, self, &net.UDPAddr{}, "")
+	self := nodeAtDistance(common.Hash{}, 0)
+	tab := newTable(lookupTestnet, self.ID, &net.UDPAddr{}, "")
 
 	// lookup on empty table returns no nodes
-	if results := tab.Lookup(target); len(results) > 0 {
+	if results := tab.Lookup(lookupTestnet.target); len(results) > 0 {
 		t.Fatalf("lookup on empty table returned %d results: %#v", len(results), results)
 	}
 	// seed table with initial node (otherwise lookup will terminate immediately)
-	tab.add([]*Node{newNode(randomID(target, 200), &net.UDPAddr{Port: 200})})
+	seed := newNode(lookupTestnet.dists[256][0], net.IP{}, 256, 0)
+	tab.add([]*Node{seed})
 
-	results := tab.Lookup(target)
+	results := tab.Lookup(lookupTestnet.target)
 	t.Logf("results:")
 	for _, e := range results {
-		t.Logf("  ld=%d, %v", logdist(target, e.ID), e.ID)
+		t.Logf("  ld=%d, %x", logdist(lookupTestnet.targetSha, e.sha), e.sha[:])
 	}
 	if len(results) != bucketSize {
 		t.Errorf("wrong number of results: got %d, want %d", len(results), bucketSize)
@@ -237,41 +252,268 @@ func TestTable_Lookup(t *testing.T) {
 	if hasDuplicates(results) {
 		t.Errorf("result set contains duplicate entries")
 	}
-	if !sortedByDistanceTo(target, results) {
+	if !sortedByDistanceTo(lookupTestnet.targetSha, results) {
 		t.Errorf("result set not sorted by distance to target")
 	}
-	if !contains(results, target) {
-		t.Errorf("result set does not contain target")
-	}
+	// TODO: check result nodes are actually closest
+}
+
+// This is the test network for the Lookup test.
+// The nodes were obtained by running testnet.mine with a random NodeID as target.
+var lookupTestnet = &preminedTestnet{
+	target:    MustHexID("166aea4f556532c6d34e8b740e5d314af7e9ac0ca79833bd751d6b665f12dfd38ec563c363b32f02aef4a80b44fd3def94612d497b99cb5f17fd24de454927ec"),
+	targetSha: common.Hash{0x5c, 0x94, 0x4e, 0xe5, 0x1c, 0x5a, 0xe9, 0xf7, 0x2a, 0x95, 0xec, 0xcb, 0x8a, 0xed, 0x3, 0x74, 0xee, 0xcb, 0x51, 0x19, 0xd7, 0x20, 0xcb, 0xea, 0x68, 0x13, 0xe8, 0xe0, 0xd6, 0xad, 0x92, 0x61},
+	dists: [257][]NodeID{
+		240: []NodeID{
+			MustHexID("2001ad5e3e80c71b952161bc0186731cf5ffe942d24a79230a0555802296238e57ea7a32f5b6f18564eadc1c65389448481f8c9338df0a3dbd18f708cbc2cbcb"),
+			MustHexID("6ba3f4f57d084b6bf94cc4555b8c657e4a8ac7b7baf23c6874efc21dd1e4f56b7eb2721e07f5242d2f1d8381fc8cae535e860197c69236798ba1ad231b105794"),
+		},
+		244: []NodeID{
+			MustHexID("696ba1f0a9d55c59246f776600542a9e6432490f0cd78f8bb55a196918df2081a9b521c3c3ba48e465a75c10768807717f8f689b0b4adce00e1c75737552a178"),
+		},
+		246: []NodeID{
+			MustHexID("d6d32178bdc38416f46ffb8b3ec9e4cb2cfff8d04dd7e4311a70e403cb62b10be1b447311b60b4f9ee221a8131fc2cbd45b96dd80deba68a949d467241facfa8"),
+			MustHexID("3ea3d04a43a3dfb5ac11cffc2319248cf41b6279659393c2f55b8a0a5fc9d12581a9d97ef5d8ff9b5abf3321a290e8f63a4f785f450dc8a672aba3ba2ff4fdab"),
+			MustHexID("2fc897f05ae585553e5c014effd3078f84f37f9333afacffb109f00ca8e7a3373de810a3946be971cbccdfd40249f9fe7f322118ea459ac71acca85a1ef8b7f4"),
+		},
+		247: []NodeID{
+			MustHexID("3155e1427f85f10a5c9a7755877748041af1bcd8d474ec065eb33df57a97babf54bfd2103575fa829115d224c523596b401065a97f74010610fce76382c0bf32"),
+			MustHexID("312c55512422cf9b8a4097e9a6ad79402e87a15ae909a4bfefa22398f03d20951933beea1e4dfa6f968212385e829f04c2d314fc2d4e255e0d3bc08792b069db"),
+			MustHexID("38643200b172dcfef857492156971f0e6aa2c538d8b74010f8e140811d53b98c765dd2d96126051913f44582e8c199ad7c6d6819e9a56483f637feaac9448aac"),
+			MustHexID("8dcab8618c3253b558d459da53bd8fa68935a719aff8b811197101a4b2b47dd2d47295286fc00cc081bb542d760717d1bdd6bec2c37cd72eca367d6dd3b9df73"),
+			MustHexID("8b58c6073dd98bbad4e310b97186c8f822d3a5c7d57af40e2136e88e315afd115edb27d2d0685a908cfe5aa49d0debdda6e6e63972691d6bd8c5af2d771dd2a9"),
+			MustHexID("2cbb718b7dc682da19652e7d9eb4fefaf7b7147d82c1c2b6805edf77b85e29fde9f6da195741467ff2638dc62c8d3e014ea5686693c15ed0080b6de90354c137"),
+			MustHexID("e84027696d3f12f2de30a9311afea8fbd313c2360daff52bb5fc8c7094d5295758bec3134e4eef24e4cdf377b40da344993284628a7a346eba94f74160998feb"),
+			MustHexID("f1357a4f04f9d33753a57c0b65ba20a5d8777abbffd04e906014491c9103fb08590e45548d37aa4bd70965e2e81ddba94f31860348df01469eec8c1829200a68"),
+			MustHexID("4ab0a75941b12892369b4490a1928c8ca52a9ad6d3dffbd1d8c0b907bc200fe74c022d011ec39b64808a39c0ca41f1d3254386c3e7733e7044c44259486461b6"),
+			MustHexID("d45150a72dc74388773e68e03133a3b5f51447fe91837d566706b3c035ee4b56f160c878c6273394daee7f56cc398985269052f22f75a8057df2fe6172765354"),
+		},
+		248: []NodeID{
+			MustHexID("6aadfce366a189bab08ac84721567483202c86590642ea6d6a14f37ca78d82bdb6509eb7b8b2f6f63c78ae3ae1d8837c89509e41497d719b23ad53dd81574afa"),
+			MustHexID("a605ecfd6069a4cf4cf7f5840e5bc0ce10d23a3ac59e2aaa70c6afd5637359d2519b4524f56fc2ca180cdbebe54262f720ccaae8c1b28fd553c485675831624d"),
+			MustHexID("29701451cb9448ca33fc33680b44b840d815be90146eb521641efbffed0859c154e8892d3906eae9934bfacee72cd1d2fa9dd050fd18888eea49da155ab0efd2"),
+			MustHexID("3ed426322dee7572b08592e1e079f8b6c6b30e10e6243edd144a6a48fdbdb83df73a6e41b1143722cb82604f2203a32758610b5d9544f44a1a7921ba001528c1"),
+			MustHexID("b2e2a2b7fdd363572a3256e75435fab1da3b16f7891a8bd2015f30995dae665d7eabfd194d87d99d5df628b4bbc7b04e5b492c596422dd8272746c7a1b0b8e4f"),
+			MustHexID("0c69c9756162c593e85615b814ce57a2a8ca2df6c690b9c4e4602731b61e1531a3bbe3f7114271554427ffabea80ad8f36fa95a49fa77b675ae182c6ccac1728"),
+			MustHexID("8d28be21d5a97b0876442fa4f5e5387f5bf3faad0b6f13b8607b64d6e448c0991ca28dd7fe2f64eb8eadd7150bff5d5666aa6ed868b84c71311f4ba9a38569dd"),
+			MustHexID("2c677e1c64b9c9df6359348a7f5f33dc79e22f0177042486d125f8b6ca7f0dc756b1f672aceee5f1746bcff80aaf6f92a8dc0c9fbeb259b3fa0da060de5ab7e8"),
+			MustHexID("3994880f94a8678f0cd247a43f474a8af375d2a072128da1ad6cae84a244105ff85e94fc7d8496f639468de7ee998908a91c7e33ef7585fff92e984b210941a1"),
+			MustHexID("b45a9153c08d002a48090d15d61a7c7dad8c2af85d4ff5bd36ce23a9a11e0709bf8d56614c7b193bc028c16cbf7f20dfbcc751328b64a924995d47b41e452422"),
+			MustHexID("057ab3a9e53c7a84b0f3fc586117a525cdd18e313f52a67bf31798d48078e325abe5cfee3f6c2533230cb37d0549289d692a29dd400e899b8552d4b928f6f907"),
+			MustHexID("0ddf663d308791eb92e6bd88a2f8cb45e4f4f35bb16708a0e6ff7f1362aa6a73fedd0a1b1557fb3365e38e1b79d6918e2fae2788728b70c9ab6b51a3b94a4338"),
+			MustHexID("f637e07ff50cc1e3731735841c4798411059f2023abcf3885674f3e8032531b0edca50fd715df6feb489b6177c345374d64f4b07d257a7745de393a107b013a5"),
+			MustHexID("e24ec7c6eec094f63c7b3239f56d311ec5a3e45bc4e622a1095a65b95eea6fe13e29f3b6b7a2cbfe40906e3989f17ac834c3102dd0cadaaa26e16ee06d782b72"),
+			MustHexID("b76ea1a6fd6506ef6e3506a4f1f60ed6287fff8114af6141b2ff13e61242331b54082b023cfea5b3083354a4fb3f9eb8be01fb4a518f579e731a5d0707291a6b"),
+			MustHexID("9b53a37950ca8890ee349b325032d7b672cab7eced178d3060137b24ef6b92a43977922d5bdfb4a3409a2d80128e02f795f9dae6d7d99973ad0e23a2afb8442f"),
+		},
+		249: []NodeID{
+			MustHexID("675ae65567c3c72c50c73bc0fd4f61f202ea5f93346ca57b551de3411ccc614fad61cb9035493af47615311b9d44ee7a161972ee4d77c28fe1ec029d01434e6a"),
+			MustHexID("8eb81408389da88536ae5800392b16ef5109d7ea132c18e9a82928047ecdb502693f6e4a4cdd18b54296caf561db937185731456c456c98bfe7de0baf0eaa495"),
+			MustHexID("2adba8b1612a541771cb93a726a38a4b88e97b18eced2593eb7daf82f05a5321ca94a72cc780c306ff21e551a932fc2c6d791e4681907b5ceab7f084c3fa2944"),
+			MustHexID("b1b4bfbda514d9b8f35b1c28961da5d5216fe50548f4066f69af3b7666a3b2e06eac646735e963e5c8f8138a2fb95af15b13b23ff00c6986eccc0efaa8ee6fb4"),
+			MustHexID("d2139281b289ad0e4d7b4243c4364f5c51aac8b60f4806135de06b12b5b369c9e43a6eb494eab860d115c15c6fbb8c5a1b0e382972e0e460af395b8385363de7"),
+			MustHexID("4a693df4b8fc5bdc7cec342c3ed2e228d7c5b4ab7321ddaa6cccbeb45b05a9f1d95766b4002e6d4791c2deacb8a667aadea6a700da28a3eea810a30395701bbc"),
+			MustHexID("ab41611195ec3c62bb8cd762ee19fb182d194fd141f4a66780efbef4b07ce916246c022b841237a3a6b512a93431157edd221e854ed2a259b72e9c5351f44d0c"),
+			MustHexID("68e8e26099030d10c3c703ae7045c0a48061fb88058d853b3e67880014c449d4311014da99d617d3150a20f1a3da5e34bf0f14f1c51fe4dd9d58afd222823176"),
+			MustHexID("3fbcacf546fb129cd70fc48de3b593ba99d3c473798bc309292aca280320e0eacc04442c914cad5c4cf6950345ba79b0d51302df88285d4e83ee3fe41339eee7"),
+			MustHexID("1d4a623659f7c8f80b6c3939596afdf42e78f892f682c768ad36eb7bfba402dbf97aea3a268f3badd8fe7636be216edf3d67ee1e08789ebbc7be625056bd7109"),
+			MustHexID("a283c474ab09da02bbc96b16317241d0627646fcc427d1fe790b76a7bf1989ced90f92101a973047ae9940c92720dffbac8eff21df8cae468a50f72f9e159417"),
+			MustHexID("dbf7e5ad7f87c3dfecae65d87c3039e14ed0bdc56caf00ce81931073e2e16719d746295512ff7937a15c3b03603e7c41a4f9df94fcd37bb200dd8f332767e9cb"),
+			MustHexID("caaa070a26692f64fc77f30d7b5ae980d419b4393a0f442b1c821ef58c0862898b0d22f74a4f8c5d83069493e3ec0b92f17dc1fe6e4cd437c1ec25039e7ce839"),
+			MustHexID("874cc8d1213beb65c4e0e1de38ef5d8165235893ac74ab5ea937c885eaab25c8d79dad0456e9fd3e9450626cac7e107b004478fb59842f067857f39a47cee695"),
+			MustHexID("d94193f236105010972f5df1b7818b55846592a0445b9cdc4eaed811b8c4c0f7c27dc8cc9837a4774656d6b34682d6d329d42b6ebb55da1d475c2474dc3dfdf4"),
+			MustHexID("edd9af6aded4094e9785637c28fccbd3980cbe28e2eb9a411048a23c2ace4bd6b0b7088a7817997b49a3dd05fc6929ca6c7abbb69438dbdabe65e971d2a794b2"),
+		},
+		250: []NodeID{
+			MustHexID("53a5bd1215d4ab709ae8fdc2ced50bba320bced78bd9c5dc92947fb402250c914891786db0978c898c058493f86fc68b1c5de8a5cb36336150ac7a88655b6c39"),
+			MustHexID("b7f79e3ab59f79262623c9ccefc8f01d682323aee56ffbe295437487e9d5acaf556a9c92e1f1c6a9601f2b9eb6b027ae1aeaebac71d61b9b78e88676efd3e1a3"),
+			MustHexID("d374bf7e8d7ffff69cc00bebff38ef5bc1dcb0a8d51c1a3d70e61ac6b2e2d6617109254b0ac224354dfbf79009fe4239e09020c483cc60c071e00b9238684f30"),
+			MustHexID("1e1eac1c9add703eb252eb991594f8f5a173255d526a855fab24ae57dc277e055bc3c7a7ae0b45d437c4f47a72d97eb7b126f2ba344ba6c0e14b2c6f27d4b1e6"),
+			MustHexID("ae28953f63d4bc4e706712a59319c111f5ff8f312584f65d7436b4cd3d14b217b958f8486bad666b4481fe879019fb1f767cf15b3e3e2711efc33b56d460448a"),
+			MustHexID("934bb1edf9c7a318b82306aca67feb3d6b434421fa275d694f0b4927afd8b1d3935b727fd4ff6e3d012e0c82f1824385174e8c6450ade59c2a43281a4b3446b6"),
+			MustHexID("9eef3f28f70ce19637519a0916555bf76d26de31312ac656cf9d3e379899ea44e4dd7ffcce923b4f3563f8a00489a34bd6936db0cbb4c959d32c49f017e07d05"),
+			MustHexID("82200872e8f871c48f1fad13daec6478298099b591bb3dbc4ef6890aa28ebee5860d07d70be62f4c0af85085a90ae8179ee8f937cf37915c67ea73e704b03ee7"),
+			MustHexID("6c75a5834a08476b7fc37ff3dc2011dc3ea3b36524bad7a6d319b18878fad813c0ba76d1f4555cacd3890c865438c21f0e0aed1f80e0a157e642124c69f43a11"),
+			MustHexID("995b873742206cb02b736e73a88580c2aacb0bd4a3c97a647b647bcab3f5e03c0e0736520a8b3600da09edf4248991fb01091ec7ff3ec7cdc8a1beae011e7aae"),
+			MustHexID("c773a056594b5cdef2e850d30891ff0e927c3b1b9c35cd8e8d53a1017001e237468e1ece3ae33d612ca3e6abb0a9169aa352e9dcda358e5af2ad982b577447db"),
+			MustHexID("2b46a5f6923f475c6be99ec6d134437a6d11f6bb4b4ac6bcd94572fa1092639d1c08aeefcb51f0912f0a060f71d4f38ee4da70ecc16010b05dd4a674aab14c3a"),
+			MustHexID("af6ab501366debbaa0d22e20e9688f32ef6b3b644440580fd78de4fe0e99e2a16eb5636bbae0d1c259df8ddda77b35b9a35cbc36137473e9c68fbc9d203ba842"),
+			MustHexID("c9f6f2dd1a941926f03f770695bda289859e85fabaf94baaae20b93e5015dc014ba41150176a36a1884adb52f405194693e63b0c464a6891cc9cc1c80d450326"),
+			MustHexID("5b116f0751526868a909b61a30b0c5282c37df6925cc03ddea556ef0d0602a9595fd6c14d371f8ed7d45d89918a032dcd22be4342a8793d88fdbeb3ca3d75bd7"),
+			MustHexID("50f3222fb6b82481c7c813b2172e1daea43e2710a443b9c2a57a12bd160dd37e20f87aa968c82ad639af6972185609d47036c0d93b4b7269b74ebd7073221c10"),
+		},
+		251: []NodeID{
+			MustHexID("9b8f702a62d1bee67bedfeb102eca7f37fa1713e310f0d6651cc0c33ea7c5477575289ccd463e5a2574a00a676a1fdce05658ba447bb9d2827f0ba47b947e894"),
+			MustHexID("b97532eb83054ed054b4abdf413bb30c00e4205545c93521554dbe77faa3cfaa5bd31ef466a107b0b34a71ec97214c0c83919720142cddac93aa7a3e928d4708"),
+			MustHexID("2f7a5e952bfb67f2f90b8441b5fadc9ee13b1dcde3afeeb3dd64bf937f86663cc5c55d1fa83952b5422763c7df1b7f2794b751c6be316ebc0beb4942e65ab8c1"),
+			MustHexID("42c7483781727051a0b3660f14faf39e0d33de5e643702ae933837d036508ab856ce7eec8ec89c4929a4901256e5233a3d847d5d4893f91bcf21835a9a880fee"),
+			MustHexID("873bae27bf1dc854408fba94046a53ab0c965cebe1e4e12290806fc62b88deb1f4a47f9e18f78fc0e7913a0c6e42ac4d0fc3a20cea6bc65f0c8a0ca90b67521e"),
+			MustHexID("a7e3a370bbd761d413f8d209e85886f68bf73d5c3089b2dc6fa42aab1ecb5162635497eed95dee2417f3c9c74a3e76319625c48ead2e963c7de877cd4551f347"),
+			MustHexID("528597534776a40df2addaaea15b6ff832ce36b9748a265768368f657e76d58569d9f30dbb91e91cf0ae7efe8f402f17aa0ae15f5c55051ba03ba830287f4c42"),
+			MustHexID("461d8bd4f13c3c09031fdb84f104ed737a52f630261463ce0bdb5704259bab4b737dda688285b8444dbecaecad7f50f835190b38684ced5e90c54219e5adf1bc"),
+			MustHexID("6ec50c0be3fd232737090fc0111caaf0bb6b18f72be453428087a11a97fd6b52db0344acbf789a689bd4f5f50f79017ea784f8fd6fe723ad6ae675b9e3b13e21"),
+			MustHexID("12fc5e2f77a83fdcc727b79d8ae7fe6a516881138d3011847ee136b400fed7cfba1f53fd7a9730253c7aa4f39abeacd04f138417ba7fcb0f36cccc3514e0dab6"),
+			MustHexID("4fdbe75914ccd0bce02101606a1ccf3657ec963e3b3c20239d5fec87673fe446d649b4f15f1fe1a40e6cfbd446dda2d31d40bb602b1093b8fcd5f139ba0eb46a"),
+			MustHexID("3753668a0f6281e425ea69b52cb2d17ab97afbe6eb84cf5d25425bc5e53009388857640668fadd7c110721e6047c9697803bd8a6487b43bb343bfa32ebf24039"),
+			MustHexID("2e81b16346637dec4410fd88e527346145b9c0a849dbf2628049ac7dae016c8f4305649d5659ec77f1e8a0fac0db457b6080547226f06283598e3740ad94849a"),
+			MustHexID("802c3cc27f91c89213223d758f8d2ecd41135b357b6d698f24d811cdf113033a81c38e0bdff574a5c005b00a8c193dc2531f8c1fa05fa60acf0ab6f2858af09f"),
+			MustHexID("fcc9a2e1ac3667026ff16192876d1813bb75abdbf39b929a92863012fe8b1d890badea7a0de36274d5c1eb1e8f975785532c50d80fd44b1a4b692f437303393f"),
+			MustHexID("6d8b3efb461151dd4f6de809b62726f5b89e9b38e9ba1391967f61cde844f7528fecf821b74049207cee5a527096b31f3ad623928cd3ce51d926fa345a6b2951"),
+		},
+		252: []NodeID{
+			MustHexID("f1ae93157cc48c2075dd5868fbf523e79e06caf4b8198f352f6e526680b78ff4227263de92612f7d63472bd09367bb92a636fff16fe46ccf41614f7a72495c2a"),
+			MustHexID("587f482d111b239c27c0cb89b51dd5d574db8efd8de14a2e6a1400c54d4567e77c65f89c1da52841212080b91604104768350276b6682f2f961cdaf4039581c7"),
+			MustHexID("e3f88274d35cefdaabdf205afe0e80e936cc982b8e3e47a84ce664c413b29016a4fb4f3a3ebae0a2f79671f8323661ed462bf4390af94c424dc8ace0c301b90f"),
+			MustHexID("0ddc736077da9a12ba410dc5ea63cbcbe7659dd08596485b2bff3435221f82c10d263efd9af938e128464be64a178b7cd22e19f400d5802f4c9df54bf89f2619"),
+			MustHexID("784aa34d833c6ce63fcc1279630113c3272e82c4ae8c126c5a52a88ac461b6baeed4244e607b05dc14e5b2f41c70a273c3804dea237f14f7a1e546f6d1309d14"),
+			MustHexID("f253a2c354ee0e27cfcae786d726753d4ad24be6516b279a936195a487de4a59dbc296accf20463749ff55293263ed8c1b6365eecb248d44e75e9741c0d18205"),
+			MustHexID("a1910b80357b3ad9b4593e0628922939614dc9056a5fbf477279c8b2c1d0b4b31d89a0c09d0d41f795271d14d3360ef08a3f821e65e7e1f56c07a36afe49c7c5"),
+			MustHexID("f1168552c2efe541160f0909b0b4a9d6aeedcf595cdf0e9b165c97e3e197471a1ee6320e93389edfba28af6eaf10de98597ad56e7ab1b504ed762451996c3b98"),
+			MustHexID("b0c8e5d2c8634a7930e1a6fd082e448c6cf9d2d8b7293558b59238815a4df926c286bf297d2049f14e8296a6eb3256af614ec1812c4f2bbe807673b58bf14c8c"),
+			MustHexID("0fb346076396a38badc342df3679b55bd7f40a609ab103411fe45082c01f12ea016729e95914b2b5540e987ff5c9b133e85862648e7f36abdfd23100d248d234"),
+			MustHexID("f736e0cc83417feaa280d9483f5d4d72d1b036cd0c6d9cbdeb8ac35ceb2604780de46dddaa32a378474e1d5ccdf79b373331c30c7911ade2ae32f98832e5de1f"),
+			MustHexID("8b02991457602f42b38b342d3f2259ae4100c354b3843885f7e4e07bd644f64dab94bb7f38a3915f8b7f11d8e3f81c28e07a0078cf79d7397e38a7b7e0c857e2"),
+			MustHexID("9221d9f04a8a184993d12baa91116692bb685f887671302999d69300ad103eb2d2c75a09d8979404c6dd28f12362f58a1a43619c493d9108fd47588a23ce5824"),
+			MustHexID("652797801744dada833fff207d67484742eea6835d695925f3e618d71b68ec3c65bdd85b4302b2cdcb835ad3f94fd00d8da07e570b41bc0d2bcf69a8de1b3284"),
+			MustHexID("d84f06fe64debc4cd0625e36d19b99014b6218375262cc2209202bdbafd7dffcc4e34ce6398e182e02fd8faeed622c3e175545864902dfd3d1ac57647cddf4c6"),
+			MustHexID("d0ed87b294f38f1d741eb601020eeec30ac16331d05880fe27868f1e454446de367d7457b41c79e202eaf9525b029e4f1d7e17d85a55f83a557c005c68d7328a"),
+		},
+		253: []NodeID{
+			MustHexID("ad4485e386e3cc7c7310366a7c38fb810b8896c0d52e55944bfd320ca294e7912d6c53c0a0cf85e7ce226e92491d60430e86f8f15cda0161ed71893fb4a9e3a1"),
+			MustHexID("36d0e7e5b7734f98c6183eeeb8ac5130a85e910a925311a19c4941b1290f945d4fc3996b12ef4966960b6fa0fb29b1604f83a0f81bd5fd6398d2e1a22e46af0c"),
+			MustHexID("7d307d8acb4a561afa23bdf0bd945d35c90245e26345ec3a1f9f7df354222a7cdcb81339c9ed6744526c27a1a0c8d10857e98df942fa433602facac71ac68a31"),
+			MustHexID("d97bf55f88c83fae36232661af115d66ca600fc4bd6d1fb35ff9bb4dad674c02cf8c8d05f317525b5522250db58bb1ecafb7157392bf5aa61b178c61f098d995"),
+			MustHexID("7045d678f1f9eb7a4613764d17bd5698796494d0bf977b16f2dbc272b8a0f7858a60805c022fc3d1fe4f31c37e63cdaca0416c0d053ef48a815f8b19121605e0"),
+			MustHexID("14e1f21418d445748de2a95cd9a8c3b15b506f86a0acabd8af44bb968ce39885b19c8822af61b3dd58a34d1f265baec30e3ae56149dc7d2aa4a538f7319f69c8"),
+			MustHexID("b9453d78281b66a4eac95a1546017111eaaa5f92a65d0de10b1122940e92b319728a24edf4dec6acc412321b1c95266d39c7b3a5d265c629c3e49a65fb022c09"),
+			MustHexID("e8a49248419e3824a00d86af422f22f7366e2d4922b304b7169937616a01d9d6fa5abf5cc01061a352dc866f48e1fa2240dbb453d872b1d7be62bdfc1d5e248c"),
+			MustHexID("bebcff24b52362f30e0589ee573ce2d86f073d58d18e6852a592fa86ceb1a6c9b96d7fb9ec7ed1ed98a51b6743039e780279f6bb49d0a04327ac7a182d9a56f6"),
+			MustHexID("d0835e5a4291db249b8d2fca9f503049988180c7d247bedaa2cf3a1bad0a76709360a85d4f9a1423b2cbc82bb4d94b47c0cde20afc430224834c49fe312a9ae3"),
+			MustHexID("6b087fe2a2da5e4f0b0f4777598a4a7fb66bf77dbd5bfc44e8a7eaa432ab585a6e226891f56a7d4f5ed11a7c57b90f1661bba1059590ca4267a35801c2802913"),
+			MustHexID("d901e5bde52d1a0f4ddf010a686a53974cdae4ebe5c6551b3c37d6b6d635d38d5b0e5f80bc0186a2c7809dbf3a42870dd09643e68d32db896c6da8ba734579e7"),
+			MustHexID("96419fb80efae4b674402bb969ebaab86c1274f29a83a311e24516d36cdf148fe21754d46c97688cdd7468f24c08b13e4727c29263393638a3b37b99ff60ebca"),
+			MustHexID("7b9c1889ae916a5d5abcdfb0aaedcc9c6f9eb1c1a4f68d0c2d034fe79ac610ce917c3abc670744150fa891bfcd8ab14fed6983fca964de920aa393fa7b326748"),
+			MustHexID("7a369b2b8962cc4c65900be046482fbf7c14f98a135bbbae25152c82ad168fb2097b3d1429197cf46d3ce9fdeb64808f908a489cc6019725db040060fdfe5405"),
+			MustHexID("47bcae48288da5ecc7f5058dfa07cf14d89d06d6e449cb946e237aa6652ea050d9f5a24a65efdc0013ccf232bf88670979eddef249b054f63f38da9d7796dbd8"),
+		},
+		254: []NodeID{
+			MustHexID("099739d7abc8abd38ecc7a816c521a1168a4dbd359fa7212a5123ab583ffa1cf485a5fed219575d6475dbcdd541638b2d3631a6c7fce7474e7fe3cba1d4d5853"),
+			MustHexID("c2b01603b088a7182d0cf7ef29fb2b04c70acb320fccf78526bf9472e10c74ee70b3fcfa6f4b11d167bd7d3bc4d936b660f2c9bff934793d97cb21750e7c3d31"),
+			MustHexID("20e4d8f45f2f863e94b45548c1ef22a11f7d36f263e4f8623761e05a64c4572379b000a52211751e2561b0f14f4fc92dd4130410c8ccc71eb4f0e95a700d4ca9"),
+			MustHexID("27f4a16cc085e72d86e25c98bd2eca173eaaee7565c78ec5a52e9e12b2211f35de81b5b45e9195de2ebfe29106742c59112b951a04eb7ae48822911fc1f9389e"),
+			MustHexID("55db5ee7d98e7f0b1c3b9d5be6f2bc619a1b86c3cdd513160ad4dcf267037a5fffad527ac15d50aeb32c59c13d1d4c1e567ebbf4de0d25236130c8361f9aac63"),
+			MustHexID("883df308b0130fc928a8559fe50667a0fff80493bc09685d18213b2db241a3ad11310ed86b0ef662b3ce21fc3d9aa7f3fc24b8d9afe17c7407e9afd3345ae548"),
+			MustHexID("c7af968cc9bc8200c3ee1a387405f7563be1dce6710a3439f42ea40657d0eae9d2b3c16c42d779605351fcdece4da637b9804e60ca08cfb89aec32c197beffa6"),
+			MustHexID("3e66f2b788e3ff1d04106b80597915cd7afa06c405a7ae026556b6e583dca8e05cfbab5039bb9a1b5d06083ffe8de5780b1775550e7218f5e98624bf7af9a0a8"),
+			MustHexID("4fc7f53764de3337fdaec0a711d35d3a923e72fa65025444d12230b3552ed43d9b2d1ad08ccb11f2d50c58809e6dd74dde910e195294fca3b47ae5a3967cc479"),
+			MustHexID("bafdfdcf6ccaa989436752fa97c77477b6baa7deb374b16c095492c529eb133e8e2f99e1977012b64767b9d34b2cf6d2048ed489bd822b5139b523f6a423167b"),
+			MustHexID("7f5d78008a4312fe059104ce80202c82b8915c2eb4411c6b812b16f7642e57c00f2c9425121f5cbac4257fe0b3e81ef5dea97ea2dbaa98f6a8b6fd4d1e5980bb"),
+			MustHexID("598c37fe78f922751a052f463aeb0cb0bc7f52b7c2a4cf2da72ec0931c7c32175d4165d0f8998f7320e87324ac3311c03f9382a5385c55f0407b7a66b2acd864"),
+			MustHexID("f758c4136e1c148777a7f3275a76e2db0b2b04066fd738554ec398c1c6cc9fb47e14a3b4c87bd47deaeab3ffd2110514c3855685a374794daff87b605b27ee2e"),
+			MustHexID("0307bb9e4fd865a49dcf1fe4333d1b944547db650ab580af0b33e53c4fef6c789531110fac801bbcbce21fc4d6f61b6d5b24abdf5b22e3030646d579f6dca9c2"),
+			MustHexID("82504b6eb49bb2c0f91a7006ce9cefdbaf6df38706198502c2e06601091fc9dc91e4f15db3410d45c6af355bc270b0f268d3dff560f956985c7332d4b10bd1ed"),
+			MustHexID("b39b5b677b45944ceebe76e76d1f051de2f2a0ec7b0d650da52135743e66a9a5dba45f638258f9a7545d9a790c7fe6d3fdf82c25425c7887323e45d27d06c057"),
+		},
+		255: []NodeID{
+			MustHexID("5c4d58d46e055dd1f093f81ee60a675e1f02f54da6206720adee4dccef9b67a31efc5c2a2949c31a04ee31beadc79aba10da31440a1f9ff2a24093c63c36d784"),
+			MustHexID("ea72161ffdd4b1e124c7b93b0684805f4c4b58d617ed498b37a145c670dbc2e04976f8785583d9c805ffbf343c31d492d79f841652bbbd01b61ed85640b23495"),
+			MustHexID("51caa1d93352d47a8e531692a3612adac1e8ac68d0a200d086c1c57ae1e1a91aa285ab242e8c52ef9d7afe374c9485b122ae815f1707b875569d0433c1c3ce85"),
+			MustHexID("c08397d5751b47bd3da044b908be0fb0e510d3149574dff7aeab33749b023bb171b5769990fe17469dbebc100bc150e798aeda426a2dcc766699a225fddd75c6"),
+			MustHexID("0222c1c194b749736e593f937fad67ee348ac57287a15c7e42877aa38a9b87732a408bca370f812efd0eedbff13e6d5b854bf3ba1dec431a796ed47f32552b09"),
+			MustHexID("03d859cd46ef02d9bfad5268461a6955426845eef4126de6be0fa4e8d7e0727ba2385b78f1a883a8239e95ebb814f2af8379632c7d5b100688eebc5841209582"),
+			MustHexID("64d5004b7e043c39ff0bd10cb20094c287721d5251715884c280a612b494b3e9e1c64ba6f67614994c7d969a0d0c0295d107d53fc225d47c44c4b82852d6f960"),
+			MustHexID("b0a5eefb2dab6f786670f35bf9641eefe6dd87fd3f1362bcab4aaa792903500ab23d88fae68411372e0813b057535a601d46e454323745a948017f6063a47b1f"),
+			MustHexID("0cc6df0a3433d448b5684d2a3ffa9d1a825388177a18f44ad0008c7bd7702f1ec0fc38b83506f7de689c3b6ecb552599927e29699eed6bb867ff08f80068b287"),
+			MustHexID("50772f7b8c03a4e153355fbbf79c8a80cf32af656ff0c7873c99911099d04a0dae0674706c357e0145ad017a0ade65e6052cb1b0d574fcd6f67da3eee0ace66b"),
+			MustHexID("1ae37829c9ef41f8b508b82259ebac76b1ed900d7a45c08b7970f25d2d48ddd1829e2f11423a18749940b6dab8598c6e416cef0efd47e46e51f29a0bc65b37cd"),
+			MustHexID("ba973cab31c2af091fc1644a93527d62b2394999e2b6ccbf158dd5ab9796a43d408786f1803ef4e29debfeb62fce2b6caa5ab2b24d1549c822a11c40c2856665"),
+			MustHexID("bc413ad270dd6ea25bddba78f3298b03b8ba6f8608ac03d06007d4116fa78ef5a0cfe8c80155089382fc7a193243ee5500082660cb5d7793f60f2d7d18650964"),
+			MustHexID("5a6a9ef07634d9eec3baa87c997b529b92652afa11473dfee41ef7037d5c06e0ddb9fe842364462d79dd31cff8a59a1b8d5bc2b810dea1d4cbbd3beb80ecec83"),
+			MustHexID("f492c6ee2696d5f682f7f537757e52744c2ae560f1090a07024609e903d334e9e174fc01609c5a229ddbcac36c9d21adaf6457dab38a25bfd44f2f0ee4277998"),
+			MustHexID("459e4db99298cb0467a90acee6888b08bb857450deac11015cced5104853be5adce5b69c740968bc7f931495d671a70cad9f48546d7cd203357fe9af0e8d2164"),
+		},
+		256: []NodeID{
+			MustHexID("a8593af8a4aef7b806b5197612017951bac8845a1917ca9a6a15dd6086d608505144990b245785c4cd2d67a295701c7aac2aa18823fb0033987284b019656268"),
+			MustHexID("d2eebef914928c3aad77fc1b2a495f52d2294acf5edaa7d8a530b540f094b861a68fe8348a46a7c302f08ab609d85912a4968eacfea0740847b29421b4795d9e"),
+			MustHexID("b14bfcb31495f32b650b63cf7d08492e3e29071fdc73cf2da0da48d4b191a70ba1a65f42ad8c343206101f00f8a48e8db4b08bf3f622c0853e7323b250835b91"),
+			MustHexID("7feaee0d818c03eb30e4e0bf03ade0f3c21ca38e938a761aa1781cf70bda8cc5cd631a6cc53dd44f1d4a6d3e2dae6513c6c66ee50cb2f0e9ad6f7e319b309fd9"),
+			MustHexID("4ca3b657b139311db8d583c25dd5963005e46689e1317620496cc64129c7f3e52870820e0ec7941d28809311df6db8a2867bbd4f235b4248af24d7a9c22d1232"),
+			MustHexID("1181defb1d16851d42dd951d84424d6bd1479137f587fa184d5a8152be6b6b16ed08bcdb2c2ed8539bcde98c80c432875f9f724737c316a2bd385a39d3cab1d8"),
+			MustHexID("d9dd818769fa0c3ec9f553c759b92476f082817252a04a47dc1777740b1731d280058c66f982812f173a294acf4944a85ba08346e2de153ba3ba41ce8a62cb64"),
+			MustHexID("bd7c4f8a9e770aa915c771b15e107ca123d838762da0d3ffc53aa6b53e9cd076cffc534ec4d2e4c334c683f1f5ea72e0e123f6c261915ed5b58ac1b59f003d88"),
+			MustHexID("3dd5739c73649d510456a70e9d6b46a855864a4a3f744e088fd8c8da11b18e4c9b5f2d7da50b1c147b2bae5ca9609ae01f7a3cdea9dce34f80a91d29cd82f918"),
+			MustHexID("f0d7df1efc439b4bcc0b762118c1cfa99b2a6143a9f4b10e3c9465125f4c9fca4ab88a2504169bbcad65492cf2f50da9dd5d077c39574a944f94d8246529066b"),
+			MustHexID("dd598b9ba441448e5fb1a6ec6c5f5aa9605bad6e223297c729b1705d11d05f6bfd3d41988b694681ae69bb03b9a08bff4beab5596503d12a39bffb5cd6e94c7c"),
+			MustHexID("3fce284ac97e567aebae681b15b7a2b6df9d873945536335883e4bbc26460c064370537f323fd1ada828ea43154992d14ac0cec0940a2bd2a3f42ec156d60c83"),
+			MustHexID("7c8dfa8c1311cb14fb29a8ac11bca23ecc115e56d9fcf7b7ac1db9066aa4eb39f8b1dabf46e192a65be95ebfb4e839b5ab4533fef414921825e996b210dd53bd"),
+			MustHexID("cafa6934f82120456620573d7f801390ed5e16ed619613a37e409e44ab355ef755e83565a913b48a9466db786f8d4fbd590bfec474c2524d4a2608d4eafd6abd"),
+			MustHexID("9d16600d0dd310d77045769fed2cb427f32db88cd57d86e49390c2ba8a9698cfa856f775be2013237226e7bf47b248871cf865d23015937d1edeb20db5e3e760"),
+			MustHexID("17be6b6ba54199b1d80eff866d348ea11d8a4b341d63ad9a6681d3ef8a43853ac564d153eb2a8737f0afc9ab320f6f95c55aa11aaa13bbb1ff422fd16bdf8188"),
+		},
+	},
 }
 
-// findnode on this transport always returns at least one node
-// that is one bucket closer to the target.
-type findnodeOracle struct {
-	t      *testing.T
-	target NodeID
+type preminedTestnet struct {
+	target    NodeID
+	targetSha common.Hash // sha3(target)
+	dists     [hashBits + 1][]NodeID
 }
 
-func (t findnodeOracle) findnode(toid NodeID, toaddr *net.UDPAddr, target NodeID) ([]*Node, error) {
-	t.t.Logf("findnode query at dist %d", toaddr.Port)
+func (tn *preminedTestnet) findnode(toid NodeID, toaddr *net.UDPAddr, target NodeID) ([]*Node, error) {
 	// current log distance is encoded in port number
-	var result []*Node
-	switch toaddr.Port {
-	case 0:
+	// fmt.Println("findnode query at dist", toaddr.Port)
+	if toaddr.Port == 0 {
 		panic("query to node at distance 0")
-	default:
-		// TODO: add more randomness to distances
-		next := toaddr.Port - 1
-		for i := 0; i < bucketSize; i++ {
-			result = append(result, &Node{ID: randomID(t.target, next), DiscPort: next})
-		}
+	}
+	if target != tn.target {
+		panic("findnode with wrong target")
+	}
+	next := uint16(toaddr.Port) - 1
+	var result []*Node
+	for i, id := range tn.dists[toaddr.Port] {
+		result = append(result, newNode(id, net.ParseIP("127.0.0.1"), next, uint16(i)))
 	}
 	return result, nil
 }
 
-func (t findnodeOracle) close()                                      {}
-func (t findnodeOracle) waitping(from NodeID) error                  { return nil }
-func (t findnodeOracle) ping(toid NodeID, toaddr *net.UDPAddr) error { return nil }
+func (*preminedTestnet) close()                                      {}
+func (*preminedTestnet) waitping(from NodeID) error                  { return nil }
+func (*preminedTestnet) ping(toid NodeID, toaddr *net.UDPAddr) error { return nil }
+
+// mine generates a testnet struct literal with nodes at
+// various distances to the given target.
+func (n *preminedTestnet) mine(target NodeID) {
+	n.target = target
+	n.targetSha = crypto.Sha3Hash(n.target[:])
+	found := 0
+	for found < bucketSize*10 {
+		k := newkey()
+		id := PubkeyID(&k.PublicKey)
+		sha := crypto.Sha3Hash(id[:])
+		ld := logdist(n.targetSha, sha)
+		if len(n.dists[ld]) < bucketSize {
+			n.dists[ld] = append(n.dists[ld], id)
+			fmt.Println("found ID with ld", ld)
+			found++
+		}
+	}
+	fmt.Println("&preminedTestnet{")
+	fmt.Printf("	target: %#v,\n", n.target)
+	fmt.Printf("	targetSha: %#v,\n", n.targetSha)
+	fmt.Printf("	dists: [%d][]NodeID{\n", len(n.dists))
+	for ld, ns := range n.dists {
+		if len(ns) == 0 {
+			continue
+		}
+		fmt.Printf("		%d: []NodeID{\n", ld)
+		for _, n := range ns {
+			fmt.Printf("			MustHexID(\"%x\"),\n", n[:])
+		}
+		fmt.Println("		},")
+	}
+	fmt.Println("	},")
+	fmt.Println("}")
+}
 
 func hasDuplicates(slice []*Node) bool {
 	seen := make(map[NodeID]bool)
@@ -284,13 +526,13 @@ func hasDuplicates(slice []*Node) bool {
 	return false
 }
 
-func sortedByDistanceTo(distbase NodeID, slice []*Node) bool {
-	var last NodeID
+func sortedByDistanceTo(distbase common.Hash, slice []*Node) bool {
+	var last common.Hash
 	for i, e := range slice {
-		if i > 0 && distcmp(distbase, e.ID, last) < 0 {
+		if i > 0 && distcmp(distbase, e.sha, last) < 0 {
 			return false
 		}
-		last = e.ID
+		last = e.sha
 	}
 	return true
 }
diff --git a/p2p/discover/udp.go b/p2p/discover/udp.go
index 65741b5f5..7213325da 100644
--- a/p2p/discover/udp.go
+++ b/p2p/discover/udp.go
@@ -15,7 +15,7 @@ import (
 	"github.com/ethereum/go-ethereum/rlp"
 )
 
-const Version = 3
+const Version = 4
 
 // Errors
 var (
@@ -49,36 +49,67 @@ const (
 // RPC request structures
 type (
 	ping struct {
-		Version    uint   // must match Version
-		IP         string // our IP
-		Port       uint16 // our port
+		Version    uint
+		From, To   rpcEndpoint
 		Expiration uint64
 	}
 
-	// reply to Ping
+	// pong is the reply to ping.
 	pong struct {
-		ReplyTok   []byte
-		Expiration uint64
+		// This field should mirror the UDP envelope address
+		// of the ping packet, which provides a way to discover the
+		// the external address (after NAT).
+		To rpcEndpoint
+
+		ReplyTok   []byte // This contains the hash of the ping packet.
+		Expiration uint64 // Absolute timestamp at which the packet becomes invalid.
 	}
 
+	// findnode is a query for nodes close to the given target.
 	findnode struct {
-		// Id to look up. The responding node will send back nodes
-		// closest to the target.
-		Target     NodeID
+		Target     NodeID // doesn't need to be an actual public key
 		Expiration uint64
 	}
 
 	// reply to findnode
 	neighbors struct {
-		Nodes      []*Node
+		Nodes      []rpcNode
 		Expiration uint64
 	}
+
+	rpcNode struct {
+		IP  net.IP // len 4 for IPv4 or 16 for IPv6
+		UDP uint16 // for discovery protocol
+		TCP uint16 // for RLPx protocol
+		ID  NodeID
+	}
+
+	rpcEndpoint struct {
+		IP  net.IP // len 4 for IPv4 or 16 for IPv6
+		UDP uint16 // for discovery protocol
+		TCP uint16 // for RLPx protocol
+	}
 )
 
-type rpcNode struct {
-	IP   string
-	Port uint16
-	ID   NodeID
+func makeEndpoint(addr *net.UDPAddr, tcpPort uint16) rpcEndpoint {
+	ip := addr.IP.To4()
+	if ip == nil {
+		ip = addr.IP.To16()
+	}
+	return rpcEndpoint{IP: ip, UDP: uint16(addr.Port), TCP: tcpPort}
+}
+
+func nodeFromRPC(rn rpcNode) (n *Node, valid bool) {
+	// TODO: don't accept localhost, LAN addresses from internet hosts
+	// TODO: check public key is on secp256k1 curve
+	if rn.IP.IsMulticast() || rn.IP.IsUnspecified() || rn.UDP == 0 {
+		return nil, false
+	}
+	return newNode(rn.ID, rn.IP, rn.UDP, rn.TCP), true
+}
+
+func nodeToRPC(n *Node) rpcNode {
+	return rpcNode{ID: n.ID, IP: n.IP, UDP: n.UDP, TCP: n.TCP}
 }
 
 type packet interface {
@@ -94,8 +125,9 @@ type conn interface {
 
 // udp implements the RPC protocol.
 type udp struct {
-	conn conn
-	priv *ecdsa.PrivateKey
+	conn        conn
+	priv        *ecdsa.PrivateKey
+	ourEndpoint rpcEndpoint
 
 	addpending chan *pending
 	gotreply   chan reply
@@ -176,6 +208,8 @@ func newUDP(priv *ecdsa.PrivateKey, c conn, natm nat.Interface, nodeDBPath strin
 			realaddr = &net.UDPAddr{IP: ext, Port: realaddr.Port}
 		}
 	}
+	// TODO: separate TCP port
+	udp.ourEndpoint = makeEndpoint(realaddr, uint16(realaddr.Port))
 	udp.Table = newTable(udp, PubkeyID(&priv.PublicKey), realaddr, nodeDBPath)
 	go udp.loop()
 	go udp.readLoop()
@@ -194,8 +228,8 @@ func (t *udp) ping(toid NodeID, toaddr *net.UDPAddr) error {
 	errc := t.pending(toid, pongPacket, func(interface{}) bool { return true })
 	t.send(toaddr, pingPacket, ping{
 		Version:    Version,
-		IP:         t.self.IP.String(),
-		Port:       uint16(t.self.TCPPort),
+		From:       t.ourEndpoint,
+		To:         makeEndpoint(toaddr, 0), // TODO: maybe use known TCP port from DB
 		Expiration: uint64(time.Now().Add(expiration).Unix()),
 	})
 	return <-errc
@@ -212,9 +246,9 @@ func (t *udp) findnode(toid NodeID, toaddr *net.UDPAddr, target NodeID) ([]*Node
 	nreceived := 0
 	errc := t.pending(toid, neighborsPacket, func(r interface{}) bool {
 		reply := r.(*neighbors)
-		for _, n := range reply.Nodes {
+		for _, rn := range reply.Nodes {
 			nreceived++
-			if n.isValid() {
+			if n, valid := nodeFromRPC(rn); valid {
 				nodes = append(nodes, n)
 			}
 		}
@@ -374,19 +408,24 @@ func (t *udp) readLoop() {
 		if err != nil {
 			return
 		}
-		packet, fromID, hash, err := decodePacket(buf[:nbytes])
-		if err != nil {
-			glog.V(logger.Debug).Infof("Bad packet from %v: %v\n", from, err)
-			continue
-		}
-		status := "ok"
-		if err := packet.handle(t, from, fromID, hash); err != nil {
-			status = err.Error()
-		}
-		glog.V(logger.Detail).Infof("<<< %v %T: %s\n", from, packet, status)
+		t.handlePacket(from, buf[:nbytes])
 	}
 }
 
+func (t *udp) handlePacket(from *net.UDPAddr, buf []byte) error {
+	packet, fromID, hash, err := decodePacket(buf)
+	if err != nil {
+		glog.V(logger.Debug).Infof("Bad packet from %v: %v\n", from, err)
+		return err
+	}
+	status := "ok"
+	if err = packet.handle(t, from, fromID, hash); err != nil {
+		status = err.Error()
+	}
+	glog.V(logger.Detail).Infof("<<< %v %T: %s\n", from, packet, status)
+	return err
+}
+
 func decodePacket(buf []byte) (packet, NodeID, []byte, error) {
 	if len(buf) < headSize+1 {
 		return nil, NodeID{}, nil, errPacketTooSmall
@@ -425,12 +464,13 @@ func (req *ping) handle(t *udp, from *net.UDPAddr, fromID NodeID, mac []byte) er
 		return errBadVersion
 	}
 	t.send(from, pongPacket, pong{
+		To:         makeEndpoint(from, req.From.TCP),
 		ReplyTok:   mac,
 		Expiration: uint64(time.Now().Add(expiration).Unix()),
 	})
 	if !t.handleReply(fromID, pingPacket, req) {
 		// Note: we're ignoring the provided IP address right now
-		go t.bond(true, fromID, from, req.Port)
+		go t.bond(true, fromID, from, req.From.TCP)
 	}
 	return nil
 }
@@ -459,12 +499,18 @@ func (req *findnode) handle(t *udp, from *net.UDPAddr, fromID NodeID, mac []byte
 		// (which is a much bigger packet than findnode) to the victim.
 		return errUnknownNode
 	}
+	target := crypto.Sha3Hash(req.Target[:])
 	t.mutex.Lock()
-	closest := t.closest(req.Target, bucketSize).entries
+	closest := t.closest(target, bucketSize).entries
 	t.mutex.Unlock()
 
+	// TODO: this conversion could use a cached version of the slice
+	closestrpc := make([]rpcNode, len(closest))
+	for i, n := range closest {
+		closestrpc[i] = nodeToRPC(n)
+	}
 	t.send(from, neighborsPacket, neighbors{
-		Nodes:      closest,
+		Nodes:      closestrpc,
 		Expiration: uint64(time.Now().Add(expiration).Unix()),
 	})
 	return nil
diff --git a/p2p/discover/udp_test.go b/p2p/discover/udp_test.go
index 47e04b85a..a2bb503ff 100644
--- a/p2p/discover/udp_test.go
+++ b/p2p/discover/udp_test.go
@@ -16,6 +16,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/logger"
 )
 
@@ -23,6 +24,15 @@ func init() {
 	logger.AddLogSystem(logger.NewStdLogSystem(os.Stdout, logpkg.LstdFlags, logger.ErrorLevel))
 }
 
+// shared test variables
+var (
+	futureExp          = uint64(time.Now().Add(10 * time.Hour).Unix())
+	testTarget         = NodeID{0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1}
+	testRemote         = rpcEndpoint{IP: net.ParseIP("1.1.1.1").To4(), UDP: 1, TCP: 2}
+	testLocalAnnounced = rpcEndpoint{IP: net.ParseIP("2.2.2.2").To4(), UDP: 3, TCP: 4}
+	testLocal          = rpcEndpoint{IP: net.ParseIP("3.3.3.3").To4(), UDP: 5, TCP: 6}
+)
+
 type udpTest struct {
 	t                   *testing.T
 	pipe                *dgramPipe
@@ -52,8 +62,7 @@ func (test *udpTest) packetIn(wantError error, ptype byte, data packet) error {
 		return test.errorf("packet (%d) encode error: %v", err)
 	}
 	test.sent = append(test.sent, enc)
-	err = data.handle(test.udp, test.remoteaddr, PubkeyID(&test.remotekey.PublicKey), enc[:macSize])
-	if err != wantError {
+	if err = test.udp.handlePacket(test.remoteaddr, enc); err != wantError {
 		return test.errorf("error mismatch: got %q, want %q", err, wantError)
 	}
 	return nil
@@ -90,18 +99,12 @@ func (test *udpTest) errorf(format string, args ...interface{}) error {
 	return err
 }
 
-// shared test variables
-var (
-	futureExp  = uint64(time.Now().Add(10 * time.Hour).Unix())
-	testTarget = MustHexID("01010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101010101")
-)
-
 func TestUDP_packetErrors(t *testing.T) {
 	test := newUDPTest(t)
 	defer test.table.Close()
 
-	test.packetIn(errExpired, pingPacket, &ping{IP: "foo", Port: 99, Version: Version})
-	test.packetIn(errBadVersion, pingPacket, &ping{IP: "foo", Port: 99, Version: 99, Expiration: futureExp})
+	test.packetIn(errExpired, pingPacket, &ping{From: testRemote, To: testLocalAnnounced, Version: Version})
+	test.packetIn(errBadVersion, pingPacket, &ping{From: testRemote, To: testLocalAnnounced, Version: 99, Expiration: futureExp})
 	test.packetIn(errUnsolicitedReply, pongPacket, &pong{ReplyTok: []byte{}, Expiration: futureExp})
 	test.packetIn(errUnknownNode, findnodePacket, &findnode{Expiration: futureExp})
 	test.packetIn(errUnsolicitedReply, neighborsPacket, &neighbors{Expiration: futureExp})
@@ -143,30 +146,25 @@ func TestUDP_findnode(t *testing.T) {
 	// put a few nodes into the table. their exact
 	// distribution shouldn't matter much, altough we need to
 	// take care not to overflow any bucket.
-	target := testTarget
-	nodes := &nodesByDistance{target: target}
+	targetHash := crypto.Sha3Hash(testTarget[:])
+	nodes := &nodesByDistance{target: targetHash}
 	for i := 0; i < bucketSize; i++ {
-		nodes.push(&Node{
-			IP:       net.IP{1, 2, 3, byte(i)},
-			DiscPort: i + 2,
-			TCPPort:  i + 2,
-			ID:       randomID(test.table.self.ID, i+2),
-		}, bucketSize)
+		nodes.push(nodeAtDistance(test.table.self.sha, i+2), bucketSize)
 	}
 	test.table.add(nodes.entries)
 
 	// ensure there's a bond with the test node,
 	// findnode won't be accepted otherwise.
-	test.table.db.updateNode(&Node{
-		ID:       PubkeyID(&test.remotekey.PublicKey),
-		IP:       test.remoteaddr.IP,
-		DiscPort: test.remoteaddr.Port,
-		TCPPort:  99,
-	})
+	test.table.db.updateNode(newNode(
+		PubkeyID(&test.remotekey.PublicKey),
+		test.remoteaddr.IP,
+		uint16(test.remoteaddr.Port),
+		99,
+	))
 	// check that closest neighbors are returned.
 	test.packetIn(nil, findnodePacket, &findnode{Target: testTarget, Expiration: futureExp})
 	test.waitPacketOut(func(p *neighbors) {
-		expected := test.table.closest(testTarget, bucketSize)
+		expected := test.table.closest(targetHash, bucketSize)
 		if len(p.Nodes) != bucketSize {
 			t.Errorf("wrong number of results: got %d, want %d", len(p.Nodes), bucketSize)
 		}
@@ -204,13 +202,17 @@ func TestUDP_findnodeMultiReply(t *testing.T) {
 
 	// send the reply as two packets.
 	list := []*Node{
-		MustParseNode("enode://ba85011c70bcc5c04d8607d3a0ed29aa6179c092cbdda10d5d32684fb33ed01bd94f588ca8f91ac48318087dcb02eaf36773a7a453f0eedd6742af668097b29c@10.0.1.16:30303"),
+		MustParseNode("enode://ba85011c70bcc5c04d8607d3a0ed29aa6179c092cbdda10d5d32684fb33ed01bd94f588ca8f91ac48318087dcb02eaf36773a7a453f0eedd6742af668097b29c@10.0.1.16:30303?discport=30304"),
 		MustParseNode("enode://81fa361d25f157cd421c60dcc28d8dac5ef6a89476633339c5df30287474520caca09627da18543d9079b5b288698b542d56167aa5c09111e55acdbbdf2ef799@10.0.1.16:30303"),
-		MustParseNode("enode://9bffefd833d53fac8e652415f4973bee289e8b1a5c6c4cbe70abf817ce8a64cee11b823b66a987f51aaa9fba0d6a91b3e6bf0d5a5d1042de8e9eeea057b217f8@10.0.1.36:30301"),
+		MustParseNode("enode://9bffefd833d53fac8e652415f4973bee289e8b1a5c6c4cbe70abf817ce8a64cee11b823b66a987f51aaa9fba0d6a91b3e6bf0d5a5d1042de8e9eeea057b217f8@10.0.1.36:30301?discport=17"),
 		MustParseNode("enode://1b5b4aa662d7cb44a7221bfba67302590b643028197a7d5214790f3bac7aaa4a3241be9e83c09cf1f6c69d007c634faae3dc1b1221793e8446c0b3a09de65960@10.0.1.16:30303"),
 	}
-	test.packetIn(nil, neighborsPacket, &neighbors{Expiration: futureExp, Nodes: list[:2]})
-	test.packetIn(nil, neighborsPacket, &neighbors{Expiration: futureExp, Nodes: list[2:]})
+	rpclist := make([]rpcNode, len(list))
+	for i := range list {
+		rpclist[i] = nodeToRPC(list[i])
+	}
+	test.packetIn(nil, neighborsPacket, &neighbors{Expiration: futureExp, Nodes: rpclist[:2]})
+	test.packetIn(nil, neighborsPacket, &neighbors{Expiration: futureExp, Nodes: rpclist[2:]})
 
 	// check that the sent neighbors are all returned by findnode
 	select {
@@ -231,7 +233,8 @@ func TestUDP_successfulPing(t *testing.T) {
 
 	done := make(chan struct{})
 	go func() {
-		test.packetIn(nil, pingPacket, &ping{IP: "foo", Port: 99, Version: Version, Expiration: futureExp})
+		// The remote side sends a ping packet to initiate the exchange.
+		test.packetIn(nil, pingPacket, &ping{From: testRemote, To: testLocalAnnounced, Version: Version, Expiration: futureExp})
 		close(done)
 	}()
 
@@ -239,12 +242,34 @@ func TestUDP_successfulPing(t *testing.T) {
 	test.waitPacketOut(func(p *pong) {
 		pinghash := test.sent[0][:macSize]
 		if !bytes.Equal(p.ReplyTok, pinghash) {
-			t.Errorf("got ReplyTok %x, want %x", p.ReplyTok, pinghash)
+			t.Errorf("got pong.ReplyTok %x, want %x", p.ReplyTok, pinghash)
+		}
+		wantTo := rpcEndpoint{
+			// The mirrored UDP address is the UDP packet sender
+			IP: test.remoteaddr.IP, UDP: uint16(test.remoteaddr.Port),
+			// The mirrored TCP port is the one from the ping packet
+			TCP: testRemote.TCP,
+		}
+		if !reflect.DeepEqual(p.To, wantTo) {
+			t.Errorf("got pong.To %v, want %v", p.To, wantTo)
 		}
 	})
 
 	// remote is unknown, the table pings back.
-	test.waitPacketOut(func(p *ping) error { return nil })
+	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)
+		}
+		wantTo := rpcEndpoint{
+			// The mirrored UDP address is the UDP packet sender.
+			IP: test.remoteaddr.IP, UDP: uint16(test.remoteaddr.Port),
+			TCP: 0,
+		}
+		if !reflect.DeepEqual(p.To, wantTo) {
+			t.Errorf("got ping.To %v, want %v", p.To, wantTo)
+		}
+		return nil
+	})
 	test.packetIn(nil, pongPacket, &pong{Expiration: futureExp})
 
 	// ping should return shortly after getting the pong packet.
@@ -259,11 +284,11 @@ func TestUDP_successfulPing(t *testing.T) {
 	if !bytes.Equal(rnode.IP, test.remoteaddr.IP) {
 		t.Errorf("node has wrong IP: got %v, want: %v", rnode.IP, test.remoteaddr.IP)
 	}
-	if rnode.DiscPort != test.remoteaddr.Port {
-		t.Errorf("node has wrong Port: got %v, want: %v", rnode.DiscPort, test.remoteaddr.Port)
+	if int(rnode.UDP) != test.remoteaddr.Port {
+		t.Errorf("node has wrong UDP port: got %v, want: %v", rnode.UDP, test.remoteaddr.Port)
 	}
-	if rnode.TCPPort != 99 {
-		t.Errorf("node has wrong Port: got %v, want: %v", rnode.TCPPort, 99)
+	if rnode.TCP != testRemote.TCP {
+		t.Errorf("node has wrong TCP port: got %v, want: %v", rnode.TCP, testRemote.TCP)
 	}
 }
 
@@ -327,7 +352,7 @@ func (c *dgramPipe) Close() error {
 }
 
 func (c *dgramPipe) LocalAddr() net.Addr {
-	return &net.UDPAddr{}
+	return &net.UDPAddr{IP: testLocal.IP, Port: int(testLocal.UDP)}
 }
 
 func (c *dgramPipe) waitPacketOut() []byte {
diff --git a/p2p/handshake_test.go b/p2p/handshake_test.go
index c22af7a9c..f618ef20d 100644
--- a/p2p/handshake_test.go
+++ b/p2p/handshake_test.go
@@ -119,14 +119,14 @@ func TestSetupConn(t *testing.T) {
 	prv0, _ := crypto.GenerateKey()
 	prv1, _ := crypto.GenerateKey()
 	node0 := &discover.Node{
-		ID:      discover.PubkeyID(&prv0.PublicKey),
-		IP:      net.IP{1, 2, 3, 4},
-		TCPPort: 33,
+		ID:  discover.PubkeyID(&prv0.PublicKey),
+		IP:  net.IP{1, 2, 3, 4},
+		TCP: 33,
 	}
 	node1 := &discover.Node{
-		ID:      discover.PubkeyID(&prv1.PublicKey),
-		IP:      net.IP{5, 6, 7, 8},
-		TCPPort: 44,
+		ID:  discover.PubkeyID(&prv1.PublicKey),
+		IP:  net.IP{5, 6, 7, 8},
+		TCP: 44,
 	}
 	hs0 := &protoHandshake{
 		Version: baseProtocolVersion,
diff --git a/p2p/peer.go b/p2p/peer.go
index bc0e6eb5f..94fa03f8d 100644
--- a/p2p/peer.go
+++ b/p2p/peer.go
@@ -15,7 +15,7 @@ import (
 )
 
 const (
-	baseProtocolVersion    = 3
+	baseProtocolVersion    = 4
 	baseProtocolLength     = uint64(16)
 	baseProtocolMaxMsgSize = 10 * 1024 * 1024
 
diff --git a/p2p/server.go b/p2p/server.go
index 5c5883ae8..e648c72c9 100644
--- a/p2p/server.go
+++ b/p2p/server.go
@@ -394,7 +394,7 @@ func (srv *Server) dialLoop() {
 }
 
 func (srv *Server) dialNode(dest *discover.Node) {
-	addr := &net.TCPAddr{IP: dest.IP, Port: dest.TCPPort}
+	addr := &net.TCPAddr{IP: dest.IP, Port: int(dest.TCP)}
 	glog.V(logger.Debug).Infof("Dialing %v\n", dest)
 	conn, err := srv.Dialer.Dial("tcp", addr.String())
 	if err != nil {
diff --git a/p2p/server_test.go b/p2p/server_test.go
index 53cc3c258..86514b650 100644
--- a/p2p/server_test.go
+++ b/p2p/server_test.go
@@ -102,7 +102,7 @@ func TestServerDial(t *testing.T) {
 
 	// tell the server to connect
 	tcpAddr := listener.Addr().(*net.TCPAddr)
-	srv.SuggestPeer(&discover.Node{IP: tcpAddr.IP, TCPPort: tcpAddr.Port})
+	srv.SuggestPeer(&discover.Node{IP: tcpAddr.IP, TCP: uint16(tcpAddr.Port)})
 
 	select {
 	case conn := <-accepted: