diff --git a/src/main/java/fr/insa/clavardator/network/ConnectionListener.java b/src/main/java/fr/insa/clavardator/network/ConnectionListener.java
index ce96473..bae3fd2 100644
--- a/src/main/java/fr/insa/clavardator/network/ConnectionListener.java
+++ b/src/main/java/fr/insa/clavardator/network/ConnectionListener.java
@@ -40,9 +40,9 @@ public class ConnectionListener {
 
 	private static class Acceptor extends Thread {
 		private boolean shouldStop = false;
-		NewConnectionCallback callback;
-		ErrorCallback errorCallback;
-		ServerSocket server;
+		private final NewConnectionCallback callback;
+		private final ErrorCallback errorCallback;
+		private ServerSocket server;
 
 		public Acceptor(NewConnectionCallback callback, ErrorCallback errorCallback) {
 			this.callback = callback;
diff --git a/src/main/java/fr/insa/clavardator/users/UserList.java b/src/main/java/fr/insa/clavardator/users/UserList.java
index b8a6407..2b65ac9 100644
--- a/src/main/java/fr/insa/clavardator/users/UserList.java
+++ b/src/main/java/fr/insa/clavardator/users/UserList.java
@@ -1,10 +1,12 @@
 package fr.insa.clavardator.users;
 
 import fr.insa.clavardator.db.DatabaseController;
+import fr.insa.clavardator.network.ConnectionListener;
 import fr.insa.clavardator.network.NetDiscoverer;
 import fr.insa.clavardator.util.ErrorCallback;
 import fr.insa.clavardator.util.Log;
 
+import java.beans.PropertyChangeEvent;
 import java.net.InetAddress;
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -21,6 +23,7 @@ public class UserList {
 
 	private final DatabaseController db = new DatabaseController();
 	private final NetDiscoverer netDiscoverer = new NetDiscoverer();
+	private final ConnectionListener connectionListener = new ConnectionListener();
 
 	public UserList() {
 	}
@@ -35,17 +38,24 @@ public class UserList {
 		netDiscoverer.discoverActiveUsers("CLAVARDATOR_BROADCAST", (ipAddr, data) -> {
 			int id = getIdFromIp(ipAddr);
 			Log.v(this.getClass().getSimpleName(), "Discovered new user: " + id);
+
 			// If already connected, do not modify
 			if (activeUsers.containsKey(id)) {
 				return;
 			}
+
 			PeerUser user = inactiveUsers.get(id);
 			if (user == null) {
 				// Username is set on TCP connection start
 				user = new PeerUser(id, "");
+				inactiveUsers.put(id, user);
 			}
 			PeerUser finalUser = user;
-			user.connect(ipAddr, () -> notifyConnectionObservers(finalUser), errorCallback);
+			user.connect(ipAddr, () -> {
+				notifyConnectionObservers(finalUser);
+				finalUser.addObserver(evt -> userChangeObserver(finalUser, evt));
+			}, errorCallback);
+
 		}, errorCallback);
 	}
 
@@ -56,10 +66,89 @@ public class UserList {
 				Throwable::printStackTrace);
 	}
 
-	private int getIdFromIp(InetAddress ipAddr) {
-		return ipAddr.hashCode();
+	public void startUserListening(ErrorCallback errorCallback) {
+		connectionListener.acceptConnection(clientSocket -> {
+			int id = getIdFromIp(clientSocket.getInetAddress());
+			Log.v(this.getClass().getSimpleName(), "new connection from user: " + id);
+
+			// If already connected, warn and return
+			if (activeUsers.containsKey(id)) {
+				Log.w(getClass().getSimpleName(), "An already connected user tried to initiate a new connection: user id " + id);
+				return;
+			}
+
+			// Get the user if already existing
+			PeerUser user = inactiveUsers.get(id);
+			// else create it
+			if (user == null) {
+				// Username is set on TCP connection start
+				user = new PeerUser(id, "");
+				inactiveUsers.put(id, user);
+			}
+
+			PeerUser finalUser = user;
+			user.connect(clientSocket, () -> {
+				notifyConnectionObservers(finalUser);
+				finalUser.addObserver(evt -> userChangeObserver(finalUser, evt));
+			}, errorCallback);
+
+		}, errorCallback);
 	}
 
+	private void userChangeObserver(PeerUser user, PropertyChangeEvent evt) {
+		int id = user.id;
+
+		if (evt.getPropertyName().equals("state")) {
+			PeerUser.State oldState = (PeerUser.State) evt.getOldValue();
+			PeerUser.State newState = (PeerUser.State) evt.getNewValue();
+
+			if ((oldState == PeerUser.State.DISCONNECTED || oldState == PeerUser.State.CONNECTING) &&
+					newState == PeerUser.State.CONNECTED) {
+				// Connection handling
+				if (!inactiveUsers.containsKey(id)) {
+					if (activeUsers.containsKey(id)) {
+						Log.e(getClass().getSimpleName(), "Tried to set state CONNECTED on an already connected user: user id " + id);
+						return;
+					} else {
+						Log.e(getClass().getSimpleName(), "Tried to set state CONNECTED on an unknown user: user id " + id);
+						return;
+					}
+				}
+
+				inactiveUsers.remove(id);
+				activeUsers.put(id, user);
+				notifyConnectionObservers(user);
+
+			} else if (oldState == PeerUser.State.CONNECTED &&
+					(newState == PeerUser.State.DISCONNECTED || newState == PeerUser.State.CONNECTING)) {
+				// Disconnection
+				if (!activeUsers.containsKey(id)) {
+					if (inactiveUsers.containsKey(id)) {
+						Log.e(getClass().getSimpleName(), "Tried to set state DISCONNECTED on an already disconnected user: user id " + id);
+						return;
+					} else {
+						Log.e(getClass().getSimpleName(), "Tried to set state DISCONNECTED on an unknown user: user id " + id);
+						return;
+					}
+				}
+
+				activeUsers.remove(id);
+				inactiveUsers.put(id, user);
+				notifyDisconnectionObservers(user);
+			}
+		}
+	}
+
+	private int getIdFromIp(InetAddress ipAddr) {
+		byte[] addr = ipAddr.getAddress();
+		int id = 0;
+		for (byte b : addr) {
+			id = (id << 8) + b;
+		}
+		return id;
+	}
+
+
 	public void addActiveUsersObserver(UserConnectionCallback connectionCallback, UserDisconnectionCallback disconnectionCallback) {
 		userConnectionObservers.add(connectionCallback);
 		userDisconnectionObservers.add(disconnectionCallback);