diff --git a/server/SHServ/Controllers/DevicesRESTAPIController.php b/server/SHServ/Controllers/DevicesRESTAPIController.php
index add788d..7297a7e 100644
--- a/server/SHServ/Controllers/DevicesRESTAPIController.php
+++ b/server/SHServ/Controllers/DevicesRESTAPIController.php
@@ -8,22 +8,54 @@
 use \SHServ\Entities\Area;
 
 class DevicesRESTAPIController extends \SHServ\Middleware\Controller {
-	public function scanning__ready_to_setup() {
-		$device_model = new Devices();
-		$devices = $device_model -> get_unregistered_devices();
+	protected function withScanLock(callable $callback) {
+		$lockFile = dirname(__DIR__, 2) . '/Cache/scan.lock';
 
-		return $this -> utils() -> response_success([
-			"devices" => $devices
-		]);
+		// Если lock устарел (старше 120 сек) — считаем его мёртвым
+		if (file_exists($lockFile) && (time() - filemtime($lockFile)) > 120) {
+			@unlink($lockFile);
+		}
+
+		$fp = @fopen($lockFile, 'c+');
+
+		if (!$fp || !flock($fp, LOCK_EX | LOCK_NB)) {
+			return $this -> utils() -> response_error("scan_in_progress");
+		}
+
+		ftruncate($fp, 0);
+		fwrite($fp, getmypid());
+		fflush($fp);
+		touch($lockFile); // обновить mtime
+
+		try {
+			return $callback();
+		} finally {
+			flock($fp, LOCK_UN);
+			fclose($fp);
+			@unlink($lockFile);
+		}
+	}
+
+	public function scanning__ready_to_setup() {
+		return $this -> withScanLock(function() {
+			$device_model = new Devices();
+			$devices = $device_model -> get_unregistered_devices();
+
+			return $this -> utils() -> response_success([
+				"devices" => $devices
+			]);
+		});
 	}
 
 	public function scanning__all() {
-		$device_model = new Devices();
-		$devices = $device_model -> scanning_localnet(FCONF["device_ip_range"][0], FCONF["device_ip_range"][1]);
+		return $this -> withScanLock(function() {
+			$device_model = new Devices();
+			$devices = $device_model -> scanning_localnet(FCONF["device_ip_range"][0], FCONF["device_ip_range"][1]);
 
-		return $this -> utils() -> response_success([
-			"devices" => $devices
-		]);
+			return $this -> utils() -> response_success([
+				"devices" => $devices
+			]);
+		});
 	}
 
 	public function setup_new_device($device_ip, $alias, $name, $description) {
diff --git a/server/SHServ/Tools/DeviceScanner.php b/server/SHServ/Tools/DeviceScanner.php
index 2d977a2..14b361d 100644
--- a/server/SHServ/Tools/DeviceScanner.php
+++ b/server/SHServ/Tools/DeviceScanner.php
@@ -20,12 +20,12 @@
    * @return array               Найденные устройства
    */
   public function scan_range(string $start_ip, string $end_ip, int $port = 80, float $timeout = 2): array {
-		$ips = $this -> generate_ip_range($start_ip, $end_ip);
-		if (empty($ips)) {
-		  return [];
-		}
+    $ips = $this -> generate_ip_range($start_ip, $end_ip);
+    if (empty($ips)) {
+      return [];
+    }
 
-		return $this -> scan_ips($ips, $port, $timeout);
+    return $this -> scan_ips($ips, $port, $timeout);
   }
 
   /**
@@ -36,164 +36,178 @@
    * @return array
    */
   public function filter_by_status(array $devices, $status): array {
-		$statuses = is_array($status) ? $status : [$status];
-		$statuses = array_map('strval', $statuses);
+    $statuses = is_array($status) ? $status : [$status];
+    $statuses = array_map('strval', $statuses);
 
-		return array_values(array_filter($devices, function ($device) use ($statuses) {
-		  if (!isset($device['status'])) {
-			return false;
-		  }
-		  return in_array((string)$device['status'], $statuses, true);
-		}));
-	  }
+    return array_values(array_filter($devices, function ($device) use ($statuses) {
+      if (!isset($device['status'])) {
+        return false;
+      }
+      return in_array((string)$device['status'], $statuses, true);
+    }));
+  }
 
-	  /**
-	   * Генерация диапазона IP (start..end включительно).
-	   */
-	  private function generate_ip_range(string $start_ip, string $end_ip): array {
-		$start = ip2long($start_ip);
-		$end   = ip2long($end_ip);
+  /**
+   * Генерация диапазона IP (start..end включительно).
+   */
+  private function generate_ip_range(string $start_ip, string $end_ip): array {
+    $start = ip2long($start_ip);
+    $end   = ip2long($end_ip);
 
-		if ($start === false || $end === false || $start > $end) {
-		  return [];
-		}
+    if ($start === false || $end === false || $start > $end) {
+      return [];
+    }
 
-		$ips = [];
-		for ($ip_long = $start; $ip_long <= $end; $ip_long++) {
-		  $ips[] = long2ip($ip_long);
-		}
+    $ips = [];
+    for ($ip_long = $start; $ip_long <= $end; $ip_long++) {
+      $ips[] = long2ip($ip_long);
+    }
 
-		return $ips;
+    return $ips;
   }
 
   private const BATCH_SIZE = 8;
 
   /**
    * Параллельное сканирование IP с curl_multi и ограничением на размер батча.
+   * Прерывается если клиент разорвал соединение (connection_aborted).
    */
   private function scan_ips(array $ips, int $port, float $timeout): array {
-		$all_devices = [];
+    $all_devices = [];
 
-		$batches = array_chunk($ips, self::BATCH_SIZE);
+    $batches = array_chunk($ips, self::BATCH_SIZE);
 
-		foreach ($batches as $batch) {
-			$batch_devices = $this -> scan_batch($batch, $port, $timeout);
-			$all_devices = array_merge($all_devices, $batch_devices);
-			usleep(200000);
-		}
+    foreach ($batches as $batch) {
+      if ((connection_status() !== CONNECTION_NORMAL)) {
+        return $all_devices;
+      }
+      $batch_devices = $this -> scan_batch($batch, $port, $timeout);
+      $all_devices = array_merge($all_devices, $batch_devices);
+      usleep(200000);
+    }
 
-		return $all_devices;
+    return $all_devices;
   }
 
   /**
    * Сканирует один батч IP через curl_multi с retry для неответивших.
+   * Retry пропускается если соединение прервано.
    */
   private function scan_batch(array $ips, int $port, float $timeout): array {
-		$devices = $this -> scan_batch_multi($ips, $port, $timeout);
+    $devices = $this -> scan_batch_multi($ips, $port, $timeout);
 
-		// Собираем IP, которые не ответили, для retry
-		$responded_ips = [];
-		foreach ($devices as $device) {
-			if (isset($device['_meta']['ip'])) {
-				$responded_ips[] = $device['_meta']['ip'];
-			}
-		}
-		$failed_ips = array_values(array_diff($ips, $responded_ips));
+    if ((connection_status() !== CONNECTION_NORMAL)) {
+      return $devices;
+    }
 
-		if (!empty($failed_ips)) {
-			usleep(500000); // 500ms backoff перед retry
-			$retry_devices = $this -> scan_batch_multi($failed_ips, $port, $timeout);
-			$devices = array_merge($devices, $retry_devices);
-		}
+    // Собираем IP, которые не ответили, для retry
+    $responded_ips = [];
+    foreach ($devices as $device) {
+      if (isset($device['_meta']['ip'])) {
+        $responded_ips[] = $device['_meta']['ip'];
+      }
+    }
+    $failed_ips = array_values(array_diff($ips, $responded_ips));
 
-		return $devices;
+    if (!empty($failed_ips)) {
+      usleep(500000); // 500ms backoff перед retry
+      $retry_devices = $this -> scan_batch_multi($failed_ips, $port, $timeout);
+      $devices = array_merge($devices, $retry_devices);
+    }
+
+    return $devices;
   }
 
   /**
    * Внутренний curl_multi проход по батчу.
+   * Прерывается если клиент разорвал соединение.
    */
   private function scan_batch_multi(array $ips, int $port, float $timeout): array {
-		$multi = curl_multi_init();
-		$handles = [];
+    $multi = curl_multi_init();
+    $handles = [];
 
-		foreach ($ips as $ip) {
-			$url = "http://{$ip}:{$port}/about";
+    foreach ($ips as $ip) {
+      $url = "http://{$ip}:{$port}/about";
 
-			$ch = curl_init();
-			curl_setopt_array($ch, [
-				CURLOPT_URL            => $url,
-				CURLOPT_RETURNTRANSFER => true,
-				CURLOPT_CONNECTTIMEOUT => $timeout,
-				CURLOPT_TIMEOUT        => $timeout,
-				CURLOPT_FOLLOWLOCATION => false,
-				CURLOPT_NOBODY         => false,
-				CURLOPT_HEADER         => false,
-			]);
+      $ch = curl_init();
+      curl_setopt_array($ch, [
+        CURLOPT_URL            => $url,
+        CURLOPT_RETURNTRANSFER => true,
+        CURLOPT_CONNECTTIMEOUT => $timeout,
+        CURLOPT_TIMEOUT        => $timeout,
+        CURLOPT_FOLLOWLOCATION => false,
+        CURLOPT_NOBODY         => false,
+        CURLOPT_HEADER         => false,
+      ]);
 
-			curl_multi_add_handle($multi, $ch);
+      curl_multi_add_handle($multi, $ch);
 
-			$handles[] = [
-				'handle' => $ch,
-				'ip'     => $ip,
-				'url'    => $url,
-			];
-		}
+      $handles[] = [
+        'handle' => $ch,
+        'ip'     => $ip,
+        'url'    => $url,
+      ];
+    }
 
-		$running = null;
-		do {
-			$status = curl_multi_exec($multi, $running);
-			if ($status > 0) {
-				break;
-			}
+    $running = null;
+    do {
+      $status = curl_multi_exec($multi, $running);
+      if ($status > 0) {
+        break;
+      }
 
-			$select_result = curl_multi_select($multi, 0.1);
-			if ($select_result === -1) {
-				usleep(100000);
-			}
-		} while ($running > 0);
+      if ((connection_status() !== CONNECTION_NORMAL)) {
+        break;
+      }
 
-		$devices = [];
+      $select_result = curl_multi_select($multi, 0.1);
+      if ($select_result === -1) {
+        usleep(100000);
+      }
+    } while ($running > 0);
 
-		foreach ($handles as $item) {
-			$ch  = $item['handle'];
-			$ip  = $item['ip'];
-			$url = $item['url'];
+    $devices = [];
 
-			$body     = curl_multi_getcontent($ch);
-			$curl_err = curl_errno($ch);
-			$http     = curl_getinfo($ch, CURLINFO_HTTP_CODE);
+    foreach ($handles as $item) {
+      $ch  = $item['handle'];
+      $ip  = $item['ip'];
+      $url = $item['url'];
 
-			curl_multi_remove_handle($multi, $ch);
-			curl_close($ch);
+      $body     = curl_multi_getcontent($ch);
+      $curl_err = curl_errno($ch);
+      $http     = curl_getinfo($ch, CURLINFO_HTTP_CODE);
 
-			if ($curl_err !== 0 || $http !== 200 || !$body) {
-				continue;
-			}
+      curl_multi_remove_handle($multi, $ch);
+      curl_close($ch);
 
-			$json = json_decode($body, true);
-			if (!is_array($json)) {
-				continue;
-			}
+      if ($curl_err !== 0 || $http !== 200 || !$body) {
+        continue;
+      }
 
-			if (!isset($json['ip_address'])) {
-				$json['ip_address'] = $ip;
-			}
-			if (!isset($json['server'])) {
-				$json['server'] = "http://{$ip}";
-			}
+      $json = json_decode($body, true);
+      if (!is_array($json)) {
+        continue;
+      }
 
-			$json['_meta'] = [
-				'ip'        => $ip,
-				'url'       => $url,
-				'http_code' => $http,
-			];
+      if (!isset($json['ip_address'])) {
+        $json['ip_address'] = $ip;
+      }
+      if (!isset($json['server'])) {
+        $json['server'] = "http://{$ip}";
+      }
 
-			$devices[] = $json;
-		}
+      $json['_meta'] = [
+        'ip'        => $ip,
+        'url'       => $url,
+        'http_code' => $http,
+      ];
 
-		curl_multi_close($multi);
+      $devices[] = $json;
+    }
 
-		return $devices;
-	}
+    curl_multi_close($multi);
 
-}
+    return $devices;
+  }
+
+}
\ No newline at end of file
diff --git a/server/SHServ/text-msgs.php b/server/SHServ/text-msgs.php
index 39dbe1e..f2d5e48 100644
--- a/server/SHServ/text-msgs.php
+++ b/server/SHServ/text-msgs.php
@@ -50,6 +50,7 @@
 	"firmware_not_found" => "Прошивка не найдена",
 	"firmware_not_compatible" => "Прошивка не совместима с устройством",
 	"ota_failed" => "Не удалось обновить прошивку на устройстве",
+	"scan_in_progress" => "Сканирование сети уже выполняется, подождите",
 
 	// Other
 	"accept_removing" => "Подтвердите удаление",
diff --git a/webclient/config.php b/webclient/config.php
index 12293ba..b1aa07f 100644
--- a/webclient/config.php
+++ b/webclient/config.php
@@ -1,9 +1,9 @@
 <?php
 
 return [
-	"version" => "0.3 dev",
-	// "server" => "http://smart-home-serv.local",
-	"server" => "http://192.168.1.101",
+	"version" => "0.4.0 dev",
+	"server" => "http://smart-home-serv.local",
+	// "server" => "http://192.168.1.101",
 	// Какие пути разрешены (белый список) — подстрой под себя
 	"allowed_prefixes" => [
 		"/api/v1/",
diff --git a/webclient/src/api/modules/devices.js b/webclient/src/api/modules/devices.js
index 37ab2eb..1b95f97 100644
--- a/webclient/src/api/modules/devices.js
+++ b/webclient/src/api/modules/devices.js
@@ -42,11 +42,11 @@
   },
 
   scanningSetup(options) {
-    return apiGet("/api/v1/devices/scanning/setup", options);
+    return apiGet("/api/v1/devices/scanning/setup", { timeoutMs: 120000, ...options });
   },
 
   scanningAll(options) {
-    return apiGet("/api/v1/devices/scanning/all", options);
+    return apiGet("/api/v1/devices/scanning/all", { timeoutMs: 120000, ...options });
   },
 
   setupNewDevice(payload) {