diff --git a/les/fetcher.go b/les/fetcher.go
index 00cb31dfb..c23af8da3 100644
--- a/les/fetcher.go
+++ b/les/fetcher.go
@@ -200,6 +200,12 @@ func (f *lightFetcher) syncLoop() {
 
 // addPeer adds a new peer to the fetcher's peer set
 func (f *lightFetcher) addPeer(p *peer) {
+	p.lock.Lock()
+	p.hasBlock = func(hash common.Hash, number uint64) bool {
+		return f.peerHasBlock(p, hash, number)
+	}
+	p.lock.Unlock()
+
 	f.lock.Lock()
 	defer f.lock.Unlock()
 
@@ -208,6 +214,10 @@ func (f *lightFetcher) addPeer(p *peer) {
 
 // removePeer removes a new peer from the fetcher's peer set
 func (f *lightFetcher) removePeer(p *peer) {
+	p.lock.Lock()
+	p.hasBlock = nil
+	p.lock.Unlock()
+
 	f.lock.Lock()
 	defer f.lock.Unlock()
 
@@ -315,7 +325,7 @@ func (f *lightFetcher) announce(p *peer, head *announceData) {
 // based on its announcements
 func (f *lightFetcher) peerHasBlock(p *peer, hash common.Hash, number uint64) bool {
 	f.lock.Lock()
-	defer f.lock.Lock()
+	defer f.lock.Unlock()
 
 	fp := f.peers[p]
 	if fp == nil || fp.root == nil {
diff --git a/les/odr.go b/les/odr.go
index 4bfbdcb4d..8878508c4 100644
--- a/les/odr.go
+++ b/les/odr.go
@@ -188,6 +188,9 @@ func (self *LesOdr) networkRequest(ctx context.Context, lreq LesOdrRequest) erro
 		var p *peer
 		if self.serverPool != nil {
 			p = self.serverPool.selectPeer(func(p *peer) (bool, uint64) {
+				if !lreq.CanSend(p) {
+					return false, 0
+				}
 				return true, p.fcServer.CanSend(lreq.GetCost(p))
 			})
 		}
diff --git a/les/odr_requests.go b/les/odr_requests.go
index f4bd51888..a4fbd79f6 100644
--- a/les/odr_requests.go
+++ b/les/odr_requests.go
@@ -36,6 +36,7 @@ import (
 
 type LesOdrRequest interface {
 	GetCost(*peer) uint64
+	CanSend(*peer) bool
 	Request(uint64, *peer) error
 	Valid(ethdb.Database, *Msg) bool // if true, keeps the retrieved object
 }
@@ -66,6 +67,11 @@ func (self *BlockRequest) GetCost(peer *peer) uint64 {
 	return peer.GetRequestCost(GetBlockBodiesMsg, 1)
 }
 
+// CanSend tells if a certain peer is suitable for serving the given request
+func (self *BlockRequest) CanSend(peer *peer) bool {
+	return peer.HasBlock(self.Hash, self.Number)
+}
+
 // Request sends an ODR request to the LES network (implementation of LesOdrRequest)
 func (self *BlockRequest) Request(reqID uint64, peer *peer) error {
 	glog.V(logger.Debug).Infof("ODR: requesting body of block %08x from peer %v", self.Hash[:4], peer.id)
@@ -121,6 +127,11 @@ func (self *ReceiptsRequest) GetCost(peer *peer) uint64 {
 	return peer.GetRequestCost(GetReceiptsMsg, 1)
 }
 
+// CanSend tells if a certain peer is suitable for serving the given request
+func (self *ReceiptsRequest) CanSend(peer *peer) bool {
+	return peer.HasBlock(self.Hash, self.Number)
+}
+
 // Request sends an ODR request to the LES network (implementation of LesOdrRequest)
 func (self *ReceiptsRequest) Request(reqID uint64, peer *peer) error {
 	glog.V(logger.Debug).Infof("ODR: requesting receipts for block %08x from peer %v", self.Hash[:4], peer.id)
@@ -171,6 +182,11 @@ func (self *TrieRequest) GetCost(peer *peer) uint64 {
 	return peer.GetRequestCost(GetProofsMsg, 1)
 }
 
+// CanSend tells if a certain peer is suitable for serving the given request
+func (self *TrieRequest) CanSend(peer *peer) bool {
+	return peer.HasBlock(self.Id.BlockHash, self.Id.BlockNumber)
+}
+
 // Request sends an ODR request to the LES network (implementation of LesOdrRequest)
 func (self *TrieRequest) Request(reqID uint64, peer *peer) error {
 	glog.V(logger.Debug).Infof("ODR: requesting trie root %08x key %08x from peer %v", self.Id.Root[:4], self.Key[:4], peer.id)
@@ -221,6 +237,11 @@ func (self *CodeRequest) GetCost(peer *peer) uint64 {
 	return peer.GetRequestCost(GetCodeMsg, 1)
 }
 
+// CanSend tells if a certain peer is suitable for serving the given request
+func (self *CodeRequest) CanSend(peer *peer) bool {
+	return peer.HasBlock(self.Id.BlockHash, self.Id.BlockNumber)
+}
+
 // Request sends an ODR request to the LES network (implementation of LesOdrRequest)
 func (self *CodeRequest) Request(reqID uint64, peer *peer) error {
 	glog.V(logger.Debug).Infof("ODR: requesting node data for hash %08x from peer %v", self.Hash[:4], peer.id)
@@ -274,6 +295,14 @@ func (self *ChtRequest) GetCost(peer *peer) uint64 {
 	return peer.GetRequestCost(GetHeaderProofsMsg, 1)
 }
 
+// CanSend tells if a certain peer is suitable for serving the given request
+func (self *ChtRequest) CanSend(peer *peer) bool {
+	peer.lock.RLock()
+	defer peer.lock.RUnlock()
+
+	return self.ChtNum <= (peer.headInfo.Number-light.ChtConfirmations)/light.ChtFrequency
+}
+
 // Request sends an ODR request to the LES network (implementation of LesOdrRequest)
 func (self *ChtRequest) Request(reqID uint64, peer *peer) error {
 	glog.V(logger.Debug).Infof("ODR: requesting CHT #%d block #%d from peer %v", self.ChtNum, self.BlockNum, peer.id)
diff --git a/les/peer.go b/les/peer.go
index 8ebbe3511..0a8db4975 100644
--- a/les/peer.go
+++ b/les/peer.go
@@ -57,6 +57,7 @@ type peer struct {
 	announceChn chan announceData
 
 	poolEntry *poolEntry
+	hasBlock  func(common.Hash, uint64) bool
 
 	fcClient       *flowcontrol.ClientNode // nil if the peer is server only
 	fcServer       *flowcontrol.ServerNode // nil if the peer is client only
@@ -135,6 +136,9 @@ func sendResponse(w p2p.MsgWriter, msgcode, reqID, bv uint64, data interface{})
 }
 
 func (p *peer) GetRequestCost(msgcode uint64, amount int) uint64 {
+	p.lock.RLock()
+	defer p.lock.RUnlock()
+
 	cost := p.fcCosts[msgcode].baseCost + p.fcCosts[msgcode].reqCost*uint64(amount)
 	if cost > p.fcServerParams.BufLimit {
 		cost = p.fcServerParams.BufLimit
@@ -142,6 +146,14 @@ func (p *peer) GetRequestCost(msgcode uint64, amount int) uint64 {
 	return cost
 }
 
+// HasBlock checks if the peer has a given block
+func (p *peer) HasBlock(hash common.Hash, number uint64) bool {
+	p.lock.RLock()
+	hashBlock := p.hasBlock
+	p.lock.RUnlock()
+	return hashBlock != nil && hashBlock(hash, number)
+}
+
 // SendAnnounce announces the availability of a number of blocks through
 // a hash notification.
 func (p *peer) SendAnnounce(request announceData) error {
diff --git a/les/server.go b/les/server.go
index 03cc2bb5e..e55616a44 100644
--- a/les/server.go
+++ b/les/server.go
@@ -349,9 +349,8 @@ func (pm *ProtocolManager) blockLoop() {
 }
 
 var (
-	lastChtKey       = []byte("LastChtNumber") // chtNum (uint64 big endian)
-	chtPrefix        = []byte("cht")           // chtPrefix + chtNum (uint64 big endian) -> trie root hash
-	chtConfirmations = light.ChtFrequency / 2
+	lastChtKey = []byte("LastChtNumber") // chtNum (uint64 big endian)
+	chtPrefix  = []byte("cht")           // chtPrefix + chtNum (uint64 big endian) -> trie root hash
 )
 
 func getChtRoot(db ethdb.Database, num uint64) common.Hash {
@@ -372,8 +371,8 @@ func makeCht(db ethdb.Database) bool {
 	headNum := core.GetBlockNumber(db, headHash)
 
 	var newChtNum uint64
-	if headNum > chtConfirmations {
-		newChtNum = (headNum - chtConfirmations) / light.ChtFrequency
+	if headNum > light.ChtConfirmations {
+		newChtNum = (headNum - light.ChtConfirmations) / light.ChtFrequency
 	}
 
 	var lastChtNum uint64
diff --git a/light/odr.go b/light/odr.go
index 679569bf9..4f6ef6b9e 100644
--- a/light/odr.go
+++ b/light/odr.go
@@ -48,6 +48,7 @@ type OdrRequest interface {
 // TrieID identifies a state or account storage trie
 type TrieID struct {
 	BlockHash, Root common.Hash
+	BlockNumber     uint64
 	AccKey          []byte
 }
 
@@ -55,9 +56,10 @@ type TrieID struct {
 // header.
 func StateTrieID(header *types.Header) *TrieID {
 	return &TrieID{
-		BlockHash: header.Hash(),
-		AccKey:    nil,
-		Root:      header.Root,
+		BlockHash:   header.Hash(),
+		BlockNumber: header.Number.Uint64(),
+		AccKey:      nil,
+		Root:        header.Root,
 	}
 }
 
@@ -66,9 +68,10 @@ func StateTrieID(header *types.Header) *TrieID {
 // checking Merkle proofs.
 func StorageTrieID(state *TrieID, addr common.Address, root common.Hash) *TrieID {
 	return &TrieID{
-		BlockHash: state.BlockHash,
-		AccKey:    crypto.Keccak256(addr[:]),
-		Root:      root,
+		BlockHash:   state.BlockHash,
+		BlockNumber: state.BlockNumber,
+		AccKey:      crypto.Keccak256(addr[:]),
+		Root:        root,
 	}
 }
 
diff --git a/light/odr_util.go b/light/odr_util.go
index 5c72f90e9..761711621 100644
--- a/light/odr_util.go
+++ b/light/odr_util.go
@@ -38,8 +38,9 @@ var (
 	ErrNoTrustedCht = errors.New("No trusted canonical hash trie")
 	ErrNoHeader     = errors.New("Header not found")
 
-	ChtFrequency  = uint64(4096)
-	trustedChtKey = []byte("TrustedCHT")
+	ChtFrequency     = uint64(4096)
+	ChtConfirmations = uint64(2048)
+	trustedChtKey    = []byte("TrustedCHT")
 )
 
 type ChtNode struct {