diff --git a/parity/main.rs b/parity/main.rs
index 2e86608ef..db6b15aee 100644
--- a/parity/main.rs
+++ b/parity/main.rs
@@ -74,7 +74,7 @@ Options:
   --peers NUM              Try to manintain that many peers [default: 25].
   --no-discovery           Disable new peer discovery.
   --upnp                   Use UPnP to try to figure out the correct network settings.
-  --node-key KEY           Specify node secret key as hex string.
+  --node-key KEY           Specify node secret key, either as 64-character hex string or input to SHA3 operation.
 
   --cache-pref-size BYTES  Specify the prefered size of the blockchain cache in bytes [default: 16384].
   --cache-max-size BYTES   Specify the maximum size of the blockchain cache in bytes [default: 262144].
@@ -216,17 +216,17 @@ impl Configuration {
 		let mut public_address = None;
 
 		if let Some(ref a) = self.args.flag_address {
-			public_address = Some(SocketAddr::from_str(a.as_ref()).expect("Invalid listen/public address given with --address"));
+			public_address = Some(SocketAddr::from_str(a.as_ref()).unwrap_or_else(|_| die!("{}: Invalid listen/public address given with --address", a)));
 			listen_address = public_address;
 		}
 		if listen_address.is_none() {
-			listen_address = Some(SocketAddr::from_str(self.args.flag_listen_address.as_ref()).expect("Invalid listen address given with --listen-address"));
+			listen_address = Some(SocketAddr::from_str(self.args.flag_listen_address.as_ref()).unwrap_or_else(|_| die!("{}: Invalid listen/public address given with --listen-address", self.args.flag_listen_address)));
 		}
 		if let Some(ref a) = self.args.flag_public_address {
 			if public_address.is_some() {
-				panic!("Conflicting flags: --address and --public-address");
+				die!("Conflicting flags provided: --address and --public-address");
 			}
-			public_address = Some(SocketAddr::from_str(a.as_ref()).expect("Invalid listen address given with --public-address"));
+			public_address = Some(SocketAddr::from_str(a.as_ref()).unwrap_or_else(|_| die!("{}: Invalid listen/public address given with --public-address", a)));
 		}
 		(listen_address, public_address)
 	}
@@ -238,7 +238,7 @@ impl Configuration {
 		let (listen, public) = self.net_addresses();
 		ret.listen_address = listen;
 		ret.public_address = public;
-		ret.use_secret = self.args.flag_node_key.as_ref().map(|s| Secret::from_str(&s).expect("Invalid key string"));
+		ret.use_secret = self.args.flag_node_key.as_ref().map(|s| Secret::from_str(&s).unwrap_or_else(|_| s.sha3()));
 		ret.discovery_enabled = !self.args.flag_no_discovery;
 		ret.ideal_peers = self.args.flag_peers;
 		let mut net_path = PathBuf::from(&self.path());
@@ -282,6 +282,7 @@ impl Configuration {
 		// Setup rpc
 		if self.args.flag_jsonrpc {
 			setup_rpc_server(service.client(), sync.clone(), &self.args.flag_jsonrpc_url, &self.args.flag_jsonrpc_cors);
+			SocketAddr::from_str(&self.args.flag_jsonrpc_url).unwrap_or_else(|_|die!("{}: Invalid JSONRPC listen address given with --jsonrpc-url. Should be of the form 'IP:port'.", self.args.flag_jsonrpc_url));
 		}
 
 		// Register IO handler
diff --git a/util/src/network/discovery.rs b/util/src/network/discovery.rs
index 01d2da52c..e2fd1c269 100644
--- a/util/src/network/discovery.rs
+++ b/util/src/network/discovery.rs
@@ -276,9 +276,6 @@ impl Discovery {
 	}
 
 	pub fn writable(&mut self) {
-		if self.send_queue.is_empty() {
-			return;
-		}
 		while !self.send_queue.is_empty() {
 			let data = self.send_queue.pop_front().unwrap();
 			match self.udp_socket.send_to(&data.payload, &data.address) {
diff --git a/util/src/network/node_table.rs b/util/src/network/node_table.rs
index ec6bad2aa..868863e8c 100644
--- a/util/src/network/node_table.rs
+++ b/util/src/network/node_table.rs
@@ -163,7 +163,7 @@ impl Display for Node {
 impl FromStr for Node {
 	type Err = UtilError;
 	fn from_str(s: &str) -> Result<Self, Self::Err> {
-		let (id, endpoint) = if &s[0..8] == "enode://" && s.len() > 136 && &s[136..137] == "@" {
+		let (id, endpoint) = if s.len() > 136 && &s[0..8] == "enode://" && &s[136..137] == "@" {
 			(try!(NodeId::from_str(&s[8..136])), try!(NodeEndpoint::from_str(&s[137..])))
 		}
 		else {