diff --git a/.travis.yml b/.travis.yml
index f7ac723e1..f66b38c51 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -41,6 +41,7 @@ env:
   - RUN_COVERAGE="false"
   - RUN_BUILD="false"
   - RUN_BENCHES="false"
+  - RUST_BACKTRACE="1"
 cache:
   apt: true
   directories:
diff --git a/ethcore/src/service.rs b/ethcore/src/service.rs
index bcfe7724f..95a891198 100644
--- a/ethcore/src/service.rs
+++ b/ethcore/src/service.rs
@@ -146,7 +146,7 @@ mod tests {
 	fn it_can_be_started() {
 		let spec = get_test_spec();
 		let temp_path = RandomTempPath::new();
-		let service = ClientService::start(ClientConfig::default(), spec, NetworkConfiguration::new_with_port(40456), &temp_path.as_path());
+		let service = ClientService::start(ClientConfig::default(), spec, NetworkConfiguration::new_local(), &temp_path.as_path());
 		assert!(service.is_ok());
 	}
 }
diff --git a/util/src/network/host.rs b/util/src/network/host.rs
index 02c576424..d4e6d13ef 100644
--- a/util/src/network/host.rs
+++ b/util/src/network/host.rs
@@ -105,6 +105,14 @@ impl NetworkConfiguration {
 		config.listen_address = Some(SocketAddr::from_str(&format!("0.0.0.0:{}", port)).unwrap());
 		config
 	}
+
+	/// Create new default configuration for localhost-only connection with random port (usefull for testing)
+	pub fn new_local() -> NetworkConfiguration {
+		let mut config = NetworkConfiguration::new();
+		config.listen_address = Some(SocketAddr::from_str("127.0.0.1:0").unwrap());
+		config.nat_enabled = false;
+		config
+	}
 }
 
 // Tokens
@@ -269,12 +277,12 @@ pub struct HostInfo {
 	pub protocol_version: u32,
 	/// Client identifier
 	pub client_version: String,
-	/// TCP connection port.
-	pub listen_port: u16,
 	/// Registered capabilities (handlers)
 	pub capabilities: Vec<CapabilityInfo>,
+	/// Local address + discovery port
+	pub local_endpoint: NodeEndpoint,
 	/// Public address + discovery port
-	public_endpoint: NodeEndpoint,
+	pub public_endpoint: Option<NodeEndpoint>,
 }
 
 impl HostInfo {
@@ -307,7 +315,7 @@ struct ProtocolTimer {
 /// Root IO handler. Manages protocol handlers, IO timers and network connections.
 pub struct Host<Message> where Message: Send + Sync + Clone {
 	pub info: RwLock<HostInfo>,
-	tcp_listener: Mutex<Option<TcpListener>>,
+	tcp_listener: Mutex<TcpListener>,
 	handshakes: Arc<RwLock<Slab<SharedHandshake>>>,
 	sessions: Arc<RwLock<Slab<SharedSession>>>,
 	discovery: Mutex<Option<Discovery>>,
@@ -321,13 +329,12 @@ pub struct Host<Message> where Message: Send + Sync + Clone {
 
 impl<Message> Host<Message> where Message: Send + Sync + Clone {
 	/// Create a new instance
-	pub fn new(config: NetworkConfiguration) -> Host<Message> {
-		let listen_address = match config.listen_address {
+	pub fn new(config: NetworkConfiguration) -> Result<Host<Message>, UtilError> {
+		let mut listen_address = match config.listen_address {
 			None => SocketAddr::from_str("0.0.0.0:30304").unwrap(),
 			Some(addr) => addr,
 		};
 
-		let udp_port = config.udp_port.unwrap_or(listen_address.port());
 		let keys = if let Some(ref secret) = config.use_secret {
 			KeyPair::from_secret(secret.clone()).unwrap()
 		} else {
@@ -342,7 +349,12 @@ impl<Message> Host<Message> where Message: Send + Sync + Clone {
 			|s| KeyPair::from_secret(s).expect("Error creating node secret key"))
 		};
 		let path = config.config_path.clone();
+		// Setup the server socket
+		let tcp_listener = try!(TcpListener::bind(&listen_address));
+		listen_address = SocketAddr::new(listen_address.ip(), try!(tcp_listener.local_addr()).port());
+		let udp_port = config.udp_port.unwrap_or(listen_address.port());
 		let local_endpoint = NodeEndpoint { address: listen_address, udp_port: udp_port };
+
 		let mut host = Host::<Message> {
 			info: RwLock::new(HostInfo {
 				keys: keys,
@@ -350,12 +362,12 @@ impl<Message> Host<Message> where Message: Send + Sync + Clone {
 				nonce: H256::random(),
 				protocol_version: PROTOCOL_VERSION,
 				client_version: version(),
-				listen_port: 0,
 				capabilities: Vec::new(),
-				public_endpoint: local_endpoint, // will be replaced by public once it is resolved
+				public_endpoint: None,
+				local_endpoint: local_endpoint,
 			}),
 			discovery: Mutex::new(None),
-			tcp_listener: Mutex::new(None),
+			tcp_listener: Mutex::new(tcp_listener),
 			handshakes: Arc::new(RwLock::new(Slab::new_starting_at(FIRST_HANDSHAKE, MAX_HANDSHAKES))),
 			sessions: Arc::new(RwLock::new(Slab::new_starting_at(FIRST_SESSION, MAX_SESSIONS))),
 			nodes: RwLock::new(NodeTable::new(path)),
@@ -365,14 +377,12 @@ impl<Message> Host<Message> where Message: Send + Sync + Clone {
 			stats: Arc::new(NetworkStats::default()),
 			pinned_nodes: Vec::new(),
 		};
-		let port = listen_address.port();
-		host.info.write().unwrap().deref_mut().listen_port = port;
 
 		let boot_nodes = host.info.read().unwrap().config.boot_nodes.clone();
 		for n in boot_nodes {
 			host.add_node(&n);
 		}
-		host
+		Ok(host)
 	}
 
 	pub fn stats(&self) -> Arc<NetworkStats> {
@@ -397,50 +407,50 @@ impl<Message> Host<Message> where Message: Send + Sync + Clone {
 		self.info.read().unwrap().client_version.clone()
 	}
 
-	pub fn client_url(&self) -> String {
-		format!("{}", Node::new(self.info.read().unwrap().id().clone(), self.info.read().unwrap().public_endpoint.clone()))
+	pub fn external_url(&self) -> Option<String> {
+		self.info.read().unwrap().public_endpoint.as_ref().map(|e| format!("{}", Node::new(self.info.read().unwrap().id().clone(), e.clone())))
 	}
 
-	fn init_public_interface(&self, io: &IoContext<NetworkIoMessage<Message>>) {
+	pub fn local_url(&self) -> String {
+		let r = format!("{}", Node::new(self.info.read().unwrap().id().clone(), self.info.read().unwrap().local_endpoint.clone()));
+		println!("{}", r);
+		r
+	}
+
+	fn init_public_interface(&self, io: &IoContext<NetworkIoMessage<Message>>) -> Result<(), UtilError> {
 		io.clear_timer(INIT_PUBLIC).unwrap();
-		let mut tcp_listener = self.tcp_listener.lock().unwrap();
-		if tcp_listener.is_some() {
-			return;
+		if self.info.read().unwrap().public_endpoint.is_some() {
+			return Ok(());
 		}
-		// public_endpoint in host info contains local adderss at this point
-		let listen_address = self.info.read().unwrap().public_endpoint.address.clone();
-		let udp_port = self.info.read().unwrap().config.udp_port.unwrap_or(listen_address.port());
+		let local_endpoint = self.info.read().unwrap().local_endpoint.clone();
 		let public_address = self.info.read().unwrap().config.public_address.clone();
 		let public_endpoint = match public_address {
 			None => {
-				let public_address = select_public_address(listen_address.port());
-				let local_endpoint = NodeEndpoint { address: public_address, udp_port: udp_port };
+				let public_address = select_public_address(local_endpoint.address.port());
+				let public_endpoint = NodeEndpoint { address: public_address, udp_port: local_endpoint.udp_port };
 				if self.info.read().unwrap().config.nat_enabled {
 					match map_external_address(&local_endpoint) {
 						Some(endpoint) => {
-							info!("NAT mappped to external address {}", endpoint.address);
+							info!("NAT mapped to external address {}", endpoint.address);
 							endpoint
 						},
-						None => local_endpoint
+						None => public_endpoint
 					}
 				} else {
-					local_endpoint
+					public_endpoint
 				}
 			}
-			Some(addr) => NodeEndpoint { address: addr, udp_port: udp_port }
+			Some(addr) => NodeEndpoint { address: addr, udp_port: local_endpoint.udp_port }
 		};
 
-		// Setup the server socket
-		*tcp_listener = Some(TcpListener::bind(&listen_address).unwrap());
-		self.info.write().unwrap().public_endpoint = public_endpoint.clone();
-		io.register_stream(TCP_ACCEPT).expect("Error registering TCP listener");
-		info!("Public node URL: {}", self.client_url());
+		self.info.write().unwrap().public_endpoint = Some(public_endpoint.clone());
+		info!("Public node URL: {}", self.external_url().unwrap());
 
 		// Initialize discovery.
 		let discovery = {
 			let info = self.info.read().unwrap();
 			if info.config.discovery_enabled && !info.config.pin {
-				Some(Discovery::new(&info.keys, listen_address.clone(), public_endpoint, DISCOVERY))
+				Some(Discovery::new(&info.keys, public_endpoint.address.clone(), public_endpoint, DISCOVERY))
 			} else { None }
 		};
 
@@ -449,11 +459,13 @@ impl<Message> Host<Message> where Message: Send + Sync + Clone {
 			for n in self.nodes.read().unwrap().unordered_entries() {
 				discovery.add_node(n.clone());
 			}
+			*self.discovery.lock().unwrap().deref_mut() = Some(discovery);
 			io.register_stream(DISCOVERY).expect("Error registering UDP listener");
 			io.register_timer(DISCOVERY_REFRESH, 7200).expect("Error registering discovery timer");
 			io.register_timer(DISCOVERY_ROUND, 300).expect("Error registering discovery timer");
-			*self.discovery.lock().unwrap().deref_mut() = Some(discovery);
 		}
+		try!(io.register_stream(TCP_ACCEPT));
+		Ok(())
 	}
 
 	fn maintain_network(&self, io: &IoContext<NetworkIoMessage<Message>>) {
@@ -567,7 +579,7 @@ impl<Message> Host<Message> where Message: Send + Sync + Clone {
 	fn accept(&self, io: &IoContext<NetworkIoMessage<Message>>) {
 		trace!(target: "network", "Accepting incoming connection");
 		loop {
-			let socket = match self.tcp_listener.lock().unwrap().as_ref().unwrap().accept() {
+			let socket = match self.tcp_listener.lock().unwrap().accept() {
 				Ok(None) => break,
 				Ok(Some((sock, _addr))) => sock,
 				Err(e) => {
@@ -861,7 +873,8 @@ impl<Message> IoHandler<NetworkIoMessage<Message>> for Host<Message> where Messa
 	fn timeout(&self, io: &IoContext<NetworkIoMessage<Message>>, token: TimerToken) {
 		match token {
 			IDLE => self.maintain_network(io),
-			INIT_PUBLIC => self.init_public_interface(io),
+			INIT_PUBLIC => self.init_public_interface(io).unwrap_or_else(|e| 
+				warn!("Error initializing public interface: {:?}", e)),
 			FIRST_SESSION ... LAST_SESSION => self.connection_timeout(token, io),
 			FIRST_HANDSHAKE ... LAST_HANDSHAKE => self.connection_timeout(token, io),
 			DISCOVERY_REFRESH => {
@@ -945,7 +958,7 @@ impl<Message> IoHandler<NetworkIoMessage<Message>> for Host<Message> where Messa
 				}
 			}
 			DISCOVERY => self.discovery.lock().unwrap().as_ref().unwrap().register_socket(event_loop).expect("Error registering discovery socket"),
-			TCP_ACCEPT => event_loop.register(self.tcp_listener.lock().unwrap().as_ref().unwrap(), Token(TCP_ACCEPT), EventSet::all(), PollOpt::edge()).expect("Error registering stream"),
+			TCP_ACCEPT => event_loop.register(self.tcp_listener.lock().unwrap().deref(), Token(TCP_ACCEPT), EventSet::all(), PollOpt::edge()).expect("Error registering stream"),
 			_ => warn!("Unexpected stream registration")
 		}
 	}
@@ -986,7 +999,7 @@ impl<Message> IoHandler<NetworkIoMessage<Message>> for Host<Message> where Messa
 				}
 			}
 			DISCOVERY => self.discovery.lock().unwrap().as_ref().unwrap().update_registration(event_loop).expect("Error reregistering discovery socket"),
-			TCP_ACCEPT => event_loop.reregister(self.tcp_listener.lock().unwrap().as_ref().unwrap(), Token(TCP_ACCEPT), EventSet::all(), PollOpt::edge()).expect("Error reregistering stream"),
+			TCP_ACCEPT => event_loop.reregister(self.tcp_listener.lock().unwrap().deref(), Token(TCP_ACCEPT), EventSet::all(), PollOpt::edge()).expect("Error reregistering stream"),
 			_ => warn!("Unexpected stream update")
 		}
 	}
@@ -1054,6 +1067,6 @@ fn host_client_url() {
 	let mut config = NetworkConfiguration::new();
 	let key = h256_from_hex("6f7b0d801bc7b5ce7bbd930b84fd0369b3eb25d09be58d64ba811091046f3aa2");
 	config.use_secret = Some(key);
-	let host: Host<u32> = Host::new(config);
-	assert!(host.client_url().starts_with("enode://101b3ef5a4ea7a1c7928e24c4c75fd053c235d7b80c22ae5c03d145d0ac7396e2a4ffff9adee3133a7b05044a5cee08115fd65145e5165d646bde371010d803c@"));
+	let host: Host<u32> = Host::new(config).unwrap();
+	assert!(host.local_url().starts_with("enode://101b3ef5a4ea7a1c7928e24c4c75fd053c235d7b80c22ae5c03d145d0ac7396e2a4ffff9adee3133a7b05044a5cee08115fd65145e5165d646bde371010d803c@"));
 }
diff --git a/util/src/network/ip_utils.rs b/util/src/network/ip_utils.rs
index b37a47064..27ff29737 100644
--- a/util/src/network/ip_utils.rs
+++ b/util/src/network/ip_utils.rs
@@ -208,6 +208,7 @@ fn can_select_public_address() {
 	assert!(pub_address.port() == 40477);
 }
 
+#[ignore]
 #[test]
 fn can_map_external_address_or_fail() {
 	let pub_address = select_public_address(40478);
diff --git a/util/src/network/mod.rs b/util/src/network/mod.rs
index 50645f2be..29f3d166c 100644
--- a/util/src/network/mod.rs
+++ b/util/src/network/mod.rs
@@ -56,7 +56,7 @@
 //! }
 //!
 //! fn main () {
-//! 	let mut service = NetworkService::<MyMessage>::start(NetworkConfiguration::new_with_port(40412)).expect("Error creating network service");
+//! 	let mut service = NetworkService::<MyMessage>::start(NetworkConfiguration::new_local()).expect("Error creating network service");
 //! 	service.register_protocol(Arc::new(MyHandler), "myproto", &[1u8]);
 //!
 //! 	// Wait for quit condition
diff --git a/util/src/network/service.rs b/util/src/network/service.rs
index 7b9388e85..49957f7e7 100644
--- a/util/src/network/service.rs
+++ b/util/src/network/service.rs
@@ -28,6 +28,7 @@ use io::*;
 pub struct NetworkService<Message> where Message: Send + Sync + Clone + 'static {
 	io_service: IoService<NetworkIoMessage<Message>>,
 	host_info: String,
+	host: Arc<Host<Message>>,
 	stats: Arc<NetworkStats>,
 	panic_handler: Arc<PanicHandler>
 }
@@ -39,15 +40,16 @@ impl<Message> NetworkService<Message> where Message: Send + Sync + Clone + 'stat
 		let mut io_service = try!(IoService::<NetworkIoMessage<Message>>::start());
 		panic_handler.forward_from(&io_service);
 
-		let host = Arc::new(Host::new(config));
+		let host = Arc::new(try!(Host::new(config)));
 		let stats = host.stats().clone();
 		let host_info = host.client_version();
-		try!(io_service.register_handler(host));
+		try!(io_service.register_handler(host.clone()));
 		Ok(NetworkService {
 			io_service: io_service,
 			host_info: host_info,
 			stats: stats,
-			panic_handler: panic_handler
+			panic_handler: panic_handler,
+			host: host,
 		})
 	}
 
@@ -71,12 +73,21 @@ impl<Message> NetworkService<Message> where Message: Send + Sync + Clone + 'stat
 		&mut self.io_service
 	}
 
-	/// Returns underlying io service.
+	/// Returns network statistics.
 	pub fn stats(&self) -> &NetworkStats {
 		&self.stats
 	}
-}
 
+	/// Returns external url if available.
+	pub fn external_url(&self) -> Option<String> {
+		self.host.external_url()
+	}
+
+	/// Returns external url if available.
+	pub fn local_url(&self) -> String {
+		self.host.local_url()
+	}
+}
 
 impl<Message> MayPanic for NetworkService<Message> where Message: Send + Sync + Clone + 'static {
 	fn on_panic<F>(&self, closure: F) where F: OnPanicListener {
diff --git a/util/src/network/session.rs b/util/src/network/session.rs
index 2f30d7376..7dbcc4229 100644
--- a/util/src/network/session.rs
+++ b/util/src/network/session.rs
@@ -315,7 +315,7 @@ impl Session {
 			.append(&host.protocol_version)
 			.append(&host.client_version)
 			.append(&host.capabilities)
-			.append(&host.listen_port)
+			.append(&host.local_endpoint.address.port())
 			.append(host.id());
 		self.connection.send_packet(&rlp.out())
 	}
diff --git a/util/src/network/tests.rs b/util/src/network/tests.rs
index f8ef588f6..b43da9320 100644
--- a/util/src/network/tests.rs
+++ b/util/src/network/tests.rs
@@ -97,23 +97,23 @@ impl NetworkProtocolHandler<TestProtocolMessage> for TestProtocol {
 
 #[test]
 fn net_service() {
-	let mut service = NetworkService::<TestProtocolMessage>::start(NetworkConfiguration::new_with_port(40414)).expect("Error creating network service");
+	let mut service = NetworkService::<TestProtocolMessage>::start(NetworkConfiguration::new_local()).expect("Error creating network service");
 	service.register_protocol(Arc::new(TestProtocol::new(false)), "myproto", &[1u8]).unwrap();
 }
 
 #[test]
 fn net_connect() {
+	::log::init_log();
 	let key1 = KeyPair::create().unwrap();
-	let mut config1 = NetworkConfiguration::new_with_port(30354);
+	let mut config1 = NetworkConfiguration::new_local();
 	config1.use_secret = Some(key1.secret().clone());
-	config1.nat_enabled = false;
 	config1.boot_nodes = vec![ ];
-	let mut config2 = NetworkConfiguration::new_with_port(30355);
-	config2.boot_nodes = vec![ format!("enode://{}@127.0.0.1:30354", key1.public().hex()) ];
-	config2.nat_enabled = false;
 	let mut service1 = NetworkService::<TestProtocolMessage>::start(config1).unwrap();
-	let mut service2 = NetworkService::<TestProtocolMessage>::start(config2).unwrap();
 	let handler1 = TestProtocol::register(&mut service1, false);
+	let mut config2 = NetworkConfiguration::new_local();
+	info!("net_connect: local URL: {}", service1.local_url());
+	config2.boot_nodes = vec![ service1.local_url() ];
+	let mut service2 = NetworkService::<TestProtocolMessage>::start(config2).unwrap();
 	let handler2 = TestProtocol::register(&mut service2, false);
 	while !handler1.got_packet() && !handler2.got_packet() && (service1.stats().sessions() == 0 || service2.stats().sessions() == 0) {
 		thread::sleep(Duration::from_millis(50));
@@ -125,16 +125,14 @@ fn net_connect() {
 #[test]
 fn net_disconnect() {
 	let key1 = KeyPair::create().unwrap();
-	let mut config1 = NetworkConfiguration::new_with_port(30364);
+	let mut config1 = NetworkConfiguration::new_local();
 	config1.use_secret = Some(key1.secret().clone());
-	config1.nat_enabled = false;
 	config1.boot_nodes = vec![ ];
-	let mut config2 = NetworkConfiguration::new_with_port(30365);
-	config2.boot_nodes = vec![ format!("enode://{}@127.0.0.1:30364", key1.public().hex()) ];
-	config2.nat_enabled = false;
 	let mut service1 = NetworkService::<TestProtocolMessage>::start(config1).unwrap();
-	let mut service2 = NetworkService::<TestProtocolMessage>::start(config2).unwrap();
 	let handler1 = TestProtocol::register(&mut service1, false);
+	let mut config2 = NetworkConfiguration::new_local();
+	config2.boot_nodes = vec![ service1.local_url() ];
+	let mut service2 = NetworkService::<TestProtocolMessage>::start(config2).unwrap();
 	let handler2 = TestProtocol::register(&mut service2, true);
 	while !(handler1.got_disconnect() && handler2.got_disconnect()) {
 		thread::sleep(Duration::from_millis(50));
@@ -145,7 +143,7 @@ fn net_disconnect() {
 
 #[test]
 fn net_timeout() {
-	let config = NetworkConfiguration::new_with_port(30346);
+	let config = NetworkConfiguration::new_local();
 	let mut service = NetworkService::<TestProtocolMessage>::start(config).unwrap();
 	let handler = TestProtocol::register(&mut service, false);
 	while !handler.got_timeout() {