diff --git a/Cargo.lock b/Cargo.lock
index 993b20fd..8489662d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -357,6 +357,14 @@ dependencies = [
  "ws2_32-sys 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "murmur3"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "net2"
 version = "0.2.26"
@@ -640,6 +648,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 name = "sync"
 version = "0.1.0"
 dependencies = [
+ "bit-vec 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "chain 0.1.0",
  "db 0.1.0",
  "ethcore-devtools 1.3.0",
@@ -649,9 +658,12 @@ dependencies = [
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "message 0.1.0",
  "miner 0.1.0",
+ "murmur3 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "p2p 0.1.0",
  "parking_lot 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "primitives 0.1.0",
+ "script 0.1.0",
+ "serialization 0.1.0",
  "test-data 0.1.0",
  "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "tokio-core 0.1.0 (git+https://github.com/debris/tokio-core)",
@@ -803,6 +815,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum memchr 0.1.11 (registry+https://github.com/rust-lang/crates.io-index)" = "d8b629fb514376c675b98c1421e80b151d3817ac42d7c667717d282761418d20"
 "checksum mio 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "410a1a0ff76f5a226f1e4e3ff1756128e65cd30166e39c3892283e2ac09d5b67"
 "checksum miow 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "d5bfc6782530ac8ace97af10a540054a37126b63b0702ddaaa243b73b5745b9a"
+"checksum murmur3 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ece7fe85164ffce69891c581b6b035a3c2f66dd3459f299d43d5efff90663e22"
 "checksum net2 0.2.26 (registry+https://github.com/rust-lang/crates.io-index)" = "5edf9cb6be97212423aed9413dd4729d62b370b5e1c571750e882cebbbc1e3e2"
 "checksum nix 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a0d95c5fa8b641c10ad0b8887454ebaafa3c92b5cd5350f8fc693adafd178e7b"
 "checksum nodrop 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "0dbbadd3f4c98dea0bd3d9b4be4c0cdaf1ab57035cb2e41fce3983db5add7cc5"
diff --git a/message/src/types/mod.rs b/message/src/types/mod.rs
index 914c0818..d6c0e865 100644
--- a/message/src/types/mod.rs
+++ b/message/src/types/mod.rs
@@ -31,6 +31,7 @@ pub use self::blocktxn::BlockTxn;
 pub use self::compactblock::CompactBlock;
 pub use self::feefilter::FeeFilter;
 pub use self::filterload::FilterLoad;
+pub use self::filterload::FilterFlags;
 pub use self::filterclear::FilterClear;
 pub use self::filteradd::FilterAdd;
 pub use self::getaddr::GetAddr;
diff --git a/primitives/src/bytes.rs b/primitives/src/bytes.rs
index 17e7d133..37958e75 100644
--- a/primitives/src/bytes.rs
+++ b/primitives/src/bytes.rs
@@ -14,6 +14,12 @@ impl Bytes {
 	}
 }
 
+impl<'a> From<&'a [u8]> for Bytes {
+	fn from(v: &[u8]) -> Self {
+		Bytes(v.into())
+	}
+}
+
 impl From<Vec<u8>> for Bytes {
 	fn from(v: Vec<u8>) -> Self {
 		Bytes(v)
diff --git a/sync/Cargo.toml b/sync/Cargo.toml
index c97deb5d..d57b7fa5 100644
--- a/sync/Cargo.toml
+++ b/sync/Cargo.toml
@@ -12,6 +12,8 @@ futures-cpupool = "0.1"
 tokio-core = { git = "https://github.com/debris/tokio-core" }
 linked-hash-map = "0.3"
 ethcore-devtools = { path = "../devtools" }
+bit-vec = "0.4.3"
+murmur3 = "0.3"
 
 chain = { path = "../chain" }
 db = { path = "../db" }
@@ -19,6 +21,8 @@ message = { path = "../message" }
 miner = { path = "../miner" }
 p2p = { path = "../p2p" }
 primitives = { path = "../primitives" }
+script = { path = "../script" }
+serialization = { path = "../serialization" }
 test-data = { path = "../test-data" }
 verification = { path = "../verification" }
 
diff --git a/sync/src/connection_filter.rs b/sync/src/connection_filter.rs
new file mode 100644
index 00000000..9cfeccbd
--- /dev/null
+++ b/sync/src/connection_filter.rs
@@ -0,0 +1,235 @@
+#![allow(dead_code)] // TODO: remove after connecting with Client
+
+use bit_vec::BitVec;
+use murmur3::murmur3_32;
+use chain::{Transaction, OutPoint};
+use ser::serialize;
+use message::types;
+use script::Script;
+
+/// Constant optimized to create large differences in the seed for different values of `hash_functions_num`.
+const SEED_OFFSET: u32 = 0xFBA4C795;
+
+/// Filter, which controls data relayed over connection.
+#[derive(Debug)]
+pub struct ConnectionFilter {
+	/// Bloom filter, if set.
+	bloom: Option<ConnectionBloom>,
+	/// Filter update type.
+	filter_flags: types::FilterFlags,
+}
+
+/// Connection bloom filter
+#[derive(Debug)]
+struct ConnectionBloom {
+	/// Filter storage.
+	filter: BitVec,
+	/// Number of hash functions to use in bloom filter.
+	hash_functions_num: u32,
+	/// Value to add to Murmur3 hash seed when calculating hash.
+	tweak: u32,
+}
+
+impl Default for ConnectionFilter {
+	fn default() -> Self {
+		ConnectionFilter {
+			bloom: None,
+			filter_flags: types::FilterFlags::None,
+		}
+	}
+}
+
+impl ConnectionFilter {
+	#[cfg(test)]
+	/// Create new connection with given filter params
+	pub fn with_filterload(message: &types::FilterLoad) -> Self {
+		ConnectionFilter {
+			bloom: Some(ConnectionBloom::new(message)),
+			filter_flags: message.flags,
+		}
+	}
+
+	/// Check if transaction is matched && update filter
+	pub fn match_update_transaction(&mut self, transaction: &Transaction) -> bool {
+		match self.bloom {
+			/// if no filter is set for the connection => match everything
+			None => true,
+			/// filter using bloom filter, then update
+			Some(ref mut bloom) => {
+				let transaction_hash = transaction.hash();
+				let mut is_match = false;
+
+				// match if filter contains any arbitrary script data element in any scriptPubKey in tx
+				for (output_index, output) in transaction.outputs.iter().enumerate() {
+					let script = Script::new(output.script_pubkey.clone());
+					for instruction in script.iter().filter_map(|i| i.ok()) {
+						if let Some(instruction_data) = instruction.data {
+							if bloom.contains(instruction_data) {
+								is_match = true;
+
+								let is_update_needed = self.filter_flags == types::FilterFlags::All
+									|| (self.filter_flags == types::FilterFlags::PubKeyOnly && (script.is_pay_to_public_key() || script.is_multisig_script()));
+								if is_update_needed {
+									bloom.insert(&serialize(&OutPoint {
+										hash: transaction_hash.clone(),
+										index: output_index as u32,
+									}));
+								}
+							}
+						}
+					}
+				}
+				if is_match {
+					return is_match;
+				}
+
+				// match if filter contains transaction itself
+				if bloom.contains(&*transaction_hash) {
+					return true;
+				}
+
+				// match if filter contains an outpoint this transaction spends
+				for input in &transaction.inputs {
+					// check if match previous output
+					let previous_output = serialize(&input.previous_output);
+					is_match = bloom.contains(&*previous_output);
+					if is_match {
+						return true;
+					}
+
+					// check if match any arbitrary script data element in any scriptSig in tx
+					let script = Script::new(input.script_sig.clone());
+					for instruction in script.iter().filter_map(|i| i.ok()) {
+						if let Some(instruction_data) = instruction.data {
+							is_match = bloom.contains(&*instruction_data);
+							if is_match {
+								return true;
+							}
+						}
+					}
+				}
+
+				// no matches
+				false
+			},
+		}
+	}
+
+	/// Load filter
+	pub fn load(&mut self, message: &types::FilterLoad) {
+		self.bloom = Some(ConnectionBloom::new(message));
+		self.filter_flags = message.flags;
+	}
+
+	/// Add filter
+	pub fn add(&mut self, message: &types::FilterAdd) {
+		// ignore if filter is not currently set
+		if let Some(ref mut bloom) = self.bloom {
+			bloom.insert(&message.data);
+		}
+	}
+
+	/// Clear filter
+	pub fn clear(&mut self) {
+		self.bloom = None;
+	}
+}
+
+impl ConnectionBloom {
+	/// Create with given parameters
+	pub fn new(message: &types::FilterLoad) -> Self {
+		ConnectionBloom {
+			filter: BitVec::from_bytes(&message.filter),
+			hash_functions_num: message.hash_functions,
+			tweak: message.tweak,
+		}
+	}
+
+	/// True if filter contains given bytes
+	pub fn contains(&self, data: &[u8]) -> bool {
+		for hash_function_idx in 0..self.hash_functions_num {
+			let murmur_seed = hash_function_idx.overflowing_mul(SEED_OFFSET).0.overflowing_add(self.tweak).0;
+			let murmur_hash = murmur3_32(&mut data.as_ref(), murmur_seed) as usize % self.filter.len();
+			if !self.filter.get(murmur_hash).expect("mod operation above") {
+				return false;
+			}
+		}
+		true
+	}
+
+	/// Add bytes to the filter
+	pub fn insert(&mut self, data: &[u8]) {
+		for hash_function_idx in 0..self.hash_functions_num {
+			let murmur_seed = hash_function_idx.overflowing_mul(SEED_OFFSET).0.overflowing_add(self.tweak).0;
+			let murmur_hash = murmur3_32(&mut data.as_ref(), murmur_seed) as usize % self.filter.len();
+			self.filter.set(murmur_hash, true);
+		}
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use std::iter::{Iterator, repeat};
+	use test_data;
+	use message::types;
+	use chain::Transaction;
+	use primitives::hash::H256;
+	use primitives::bytes::Bytes;
+	use super::{ConnectionFilter, ConnectionBloom};
+
+	fn default_filterload() -> types::FilterLoad {
+		types::FilterLoad {
+			filter: Bytes::from(repeat(0u8).take(1024).collect::<Vec<_>>()),
+			hash_functions: 10,
+			tweak: 5,
+			flags: types::FilterFlags::None,
+		}
+	}
+
+	fn make_filteradd(data: &[u8]) -> types::FilterAdd {
+		types::FilterAdd {
+			data: data.into(),
+		}
+	}
+
+	#[test]
+	fn bloom_insert_data() {
+		let mut bloom = ConnectionBloom::new(&default_filterload());
+
+		assert!(!bloom.contains(&*H256::default()));
+
+		bloom.insert(&*H256::default());
+		assert!(bloom.contains(&*H256::default()));
+	}
+
+	#[test]
+	fn connection_filter_matches_transaction_by_hash() {
+		let tx1: Transaction = test_data::TransactionBuilder::with_output(10).into();
+		let tx2: Transaction = test_data::TransactionBuilder::with_output(20).into();
+
+		let mut filter = ConnectionFilter::with_filterload(&default_filterload());
+
+		assert!(!filter.match_update_transaction(&tx1));
+		assert!(!filter.match_update_transaction(&tx2));
+
+		filter.add(&make_filteradd(&*tx1.hash()));
+
+		assert!(filter.match_update_transaction(&tx1));
+		assert!(!filter.match_update_transaction(&tx2));
+	}
+
+	#[test]
+	fn connection_filter_matches_transaction_by_output_script_data_element() {
+		// TODO
+	}
+
+	#[test]
+	fn connection_filter_matches_transaction_by_previous_output_point() {
+		// TODO
+	}
+
+	#[test]
+	fn connection_filter_matches_transaction_by_input_script_data_element() {
+		// TODO
+	}
+}
diff --git a/sync/src/lib.rs b/sync/src/lib.rs
index bcf96928..29c6c50b 100644
--- a/sync/src/lib.rs
+++ b/sync/src/lib.rs
@@ -9,16 +9,21 @@ extern crate message;
 extern crate p2p;
 extern crate parking_lot;
 extern crate linked_hash_map;
+extern crate bit_vec;
+extern crate murmur3;
 extern crate primitives;
 extern crate test_data;
 extern crate time;
 extern crate verification;
 extern crate miner;
+extern crate script;
+extern crate serialization as ser;
 #[cfg(test)]
 extern crate ethcore_devtools as devtools;
 
 mod best_headers_chain;
 mod blocks_writer;
+mod connection_filter;
 mod hash_queue;
 mod inbound_connection;
 mod inbound_connection_factory;
diff --git a/sync/src/local_node.rs b/sync/src/local_node.rs
index 64306c1a..f97e1c61 100644
--- a/sync/src/local_node.rs
+++ b/sync/src/local_node.rs
@@ -11,6 +11,8 @@ use synchronization_server::{Server, SynchronizationServer};
 use synchronization_verifier::AsyncVerifier;
 use primitives::hash::H256;
 
+// TODO: check messages before processing (filterload' filter is max 36000, nHashFunc is <= 50, etc)
+
 pub type LocalNodeRef = Arc<LocalNode<LocalSynchronizationTaskExecutor, SynchronizationServer, SynchronizationClient<LocalSynchronizationTaskExecutor, AsyncVerifier>>>;
 
 /// Local synchronization node
diff --git a/sync/src/synchronization_server.rs b/sync/src/synchronization_server.rs
index 63dc6006..67185ea9 100644
--- a/sync/src/synchronization_server.rs
+++ b/sync/src/synchronization_server.rs
@@ -365,7 +365,7 @@ impl Server for SynchronizationServer {
 	fn serve_getheaders(&self, peer_index: usize, message: types::GetHeaders, id: Option<u32>) -> Option<IndexedServerTask> {
 		if let Some(best_common_block) = self.locate_known_block_header(message.block_locator_hashes) {
 			trace!(target: "sync", "Best common block header with peer#{} is block#{}: {:?}", peer_index, best_common_block.number, best_common_block.hash.to_reversed_str());
-			let server_task_index = id.map_or_else(|| ServerTaskIndex::None, |id| ServerTaskIndex::Final(id));
+			let server_task_index = id.map_or_else(|| ServerTaskIndex::None, ServerTaskIndex::Final);
 			let task = IndexedServerTask::new(ServerTask::ServeGetHeaders(best_common_block, message.hash_stop), server_task_index);
 			Some(task)
 		}