diff --git a/src/judas_server/backend/backend_server.py b/src/judas_server/backend/backend_server.py
index babb523..7311cfa 100644
--- a/src/judas_server/backend/backend_server.py
+++ b/src/judas_server/backend/backend_server.py
@@ -164,71 +164,67 @@ class BackendServer:
         try:
             if mask & selectors.EVENT_READ:
                 self._receive_inbound(sock, client)
-                if client.inbound:
-                    if client.mac_id is None:
-                        # expect HELLO message
-                        try:
-                            msg = Message.from_bytes(client.inbound)
-                            if (
-                                msg.category == Category.CONTROL
-                                and msg.action == ControlAction.HELLO
-                                and msg.payload.get("mac") is not None
-                            ):
-                                client.mac_id = msg.payload["mac"]
-                                if (
-                                    client.mac_id in self.clients
-                                    and self.clients[client.mac_id].status
-                                    == "connected"
-                                ):
-                                    old_client: Client = self.clients[
-                                        client.mac_id
-                                    ]
-                                    self.logger.warning(
-                                        f"Client {client.mac_id} is already connected from {old_client.addr}, disconnecting old client..."
-                                    )
-                                    self._disconnect(old_client)
-                                    # TODO: tell client not to reconnect
-                                self.clients[client.mac_id] = client
-                                self.logger.info(
-                                    f"[+] Registered new client {client}"
-                                )
-                            else:
-                                self.logger.error(
-                                    f"Expected HELLO message from {client}, got {msg}"
-                                )
-                                self._disconnect(client)
-                                return
-                        except Exception as e:
-                            self.logger.error(
-                                f"Failed to parse HELLO message from {client}: {e}"
-                            )
-                            self._disconnect(client)
-                            return
-
-                    while b"\n" in client.inbound:
-                        line, client.inbound = client.inbound.split(b"\n", 1)
-                        self.logger.debug(
-                            f"[<] Complete message from {client}: {line!r}"
-                        )
-                        try:
-                            msg = Message.from_bytes(line)
-                            self.logger.info(f"[.] Parsed message {msg.id}")
-                            if msg.ack_required:
-                                self._send_ack(client, target_id=msg.id)
-
-                        except Exception as e:
-                            self.logger.error(
-                                f"Failed to parse message from {client}: {e}"
-                            )
-                            self._disconnect(client)
-                            return
-
-                else:
+                if not client.inbound:
                     self._disconnect(client)
+                    return
 
-            if mask & selectors.EVENT_WRITE:
-                if client.outbound:
-                    self._send_outbound(sock, client)
+                if client.mac_id is None:
+                    # expect HELLO message
+                    try:
+                        msg = Message.from_bytes(client.inbound)
+                    except Exception as e:
+                        self.logger.error(
+                            f"Failed to parse HELLO message from {client}: {e}"
+                        )
+                        self._disconnect(client)
+                        return
+
+                    if (
+                        msg.category == Category.CONTROL
+                        and msg.action == ControlAction.HELLO
+                        and msg.payload.get("mac") is not None
+                    ):
+                        client.mac_id = msg.payload["mac"]
+                        if (
+                            client.mac_id in self.clients
+                            and self.clients[client.mac_id].status
+                            == "connected"
+                        ):
+                            old_client: Client = self.clients[client.mac_id]
+                            self.logger.warning(
+                                f"Client {client.mac_id} is already connected from {old_client.addr}, disconnecting old client..."
+                            )
+                            self.send_close(old_client)
+                            # self._disconnect(old_client)
+                            # TODO: tell client not to reconnect
+                        self.clients[client.mac_id] = client
+                        self.logger.info(f"[+] Registered new client {client}")
+                    else:
+                        self.logger.error(
+                            f"Expected HELLO message from {client}, got {msg}"
+                        )
+                        self._disconnect(client)
+                        return
+
+                while b"\n" in client.inbound:
+                    line, client.inbound = client.inbound.split(b"\n", 1)
+                    self.logger.debug(
+                        f"[<] Complete message from {client}: {line!r}"
+                    )
+                    try:
+                        msg = Message.from_bytes(line)
+                        self.logger.info(f"[.] Parsed message {msg.id}")
+                        if msg.ack_required:
+                            self.send_ack(client, target_id=msg.id)
+                    except Exception as e:
+                        self.logger.error(
+                            f"Failed to parse message from {client}: {e}"
+                        )
+                        self._disconnect(client)
+                        return
+
+            if mask & selectors.EVENT_WRITE and client.outbound:
+                self._send_outbound(sock, client)
 
         except ConnectionResetError as e:
             self.logger.error(f"Connection reset by {client}, disconnect: {e}")