diff --git a/backend/src/routes/devices.ts b/backend/src/routes/devices.ts
index fd1644c..3e91794 100644
--- a/backend/src/routes/devices.ts
+++ b/backend/src/routes/devices.ts
@@ -1873,32 +1873,66 @@ router.post('/:id/tools/capture', requireWrite, async (req: Request, res: Respon
 });
 
 // POST /api/devices/:id/tools/btest — bandwidth test via RouterOS
+// If target_device_id is provided: automatically enable/disable btest server on the target device.
+// If only address is provided: manual mode — user must ensure the btest server is already running.
 router.post('/:id/tools/btest', requireWrite, async (req: Request, res: Response) => {
-  const { address, direction = 'both', duration = 5, protocol = 'tcp' } = req.body as {
-    address?: string; direction?: string; duration?: number; protocol?: string;
+  const { target_device_id, address, direction = 'both', duration = 5, protocol = 'tcp' } = req.body as {
+    target_device_id?: number; address?: string; direction?: string; duration?: number; protocol?: string;
   };
-  if (!address) return res.status(400).json({ error: 'address is required' });
+  if (!target_device_id && !address) {
+    return res.status(400).json({ error: 'target_device_id or address is required' });
+  }
   const testSec = Math.min(Math.max(1, Number(duration) || 5), 30);
 
   const device = await getToolDevice(req.params.id);
   if (!device) return res.status(404).json({ error: 'Device not found' });
 
+  // Resolve target: either a managed device (auto server management) or a manual IP
+  let targetAddress = address ?? '';
+  let targetUser: string | undefined;
+  let targetPassword: string | undefined;
+  let serverClient: RouterOSClient | null = null;
+
+  if (target_device_id) {
+    const target = await getToolDevice(String(target_device_id));
+    if (!target) return res.status(404).json({ error: 'Target device not found' });
+    targetAddress = target.ip_address;
+    targetUser = target.api_username;
+    targetPassword = decrypt(target.api_password_encrypted);
+    serverClient = new RouterOSClient(
+      target.ip_address, target.api_port, target.api_username, targetPassword, 15_000, 20_000
+    );
+  }
+
   const client = new RouterOSClient(
     device.ip_address, device.api_port, device.api_username,
     decrypt(device.api_password_encrypted),
     15_000,
-    (testSec + 10) * 1000
+    (testSec + 15) * 1000
   );
+
   try {
+    // Enable bandwidth-test server on target device before running test
+    if (serverClient) {
+      await serverClient.connect();
+      await serverClient.execute('/tool/bandwidth-server/set', { enabled: 'yes', authenticate: 'yes' });
+      serverClient.disconnect();
+    }
+
     await client.connect();
-    const rows = await client.executeStreaming('/tool/bandwidth-test', {
-      address,
+    const btestParams: Record<string, string> = {
+      address: targetAddress,
       direction: ['receive', 'transmit', 'both'].includes(direction) ? direction : 'both',
       duration: String(testSec),
       protocol: ['tcp', 'udp'].includes(protocol) ? protocol : 'tcp',
-    }, (testSec + 10) * 1000);
+    };
+    // When testing against a managed device, authenticate with its RouterOS credentials
+    if (targetUser) btestParams['user'] = targetUser;
+    if (targetPassword) btestParams['password'] = targetPassword;
+
+    const rows = await client.executeStreaming('/tool/bandwidth-test', btestParams, (testSec + 15) * 1000);
+    client.disconnect();
 
-    // Return the final summary row (last row that has tx/rx total averages)
     const lastRow = rows.filter((r) => r['tx-total-average'] !== undefined || r['rx-total-average'] !== undefined).at(-1);
     const toMbps = (v: string | undefined) => v ? Math.round(parseInt(v) / 1_000_000) : 0;
 
@@ -1908,12 +1942,23 @@ router.post('/:id/tools/btest', requireWrite, async (req: Request, res: Response
       direction,
       protocol,
       duration: testSec,
+      target_ip: targetAddress,
       raw: lastRow ?? rows.at(-1) ?? null,
     });
   } catch (err) {
     return res.status(500).json({ error: (err as Error).message });
   } finally {
     client.disconnect();
+    // Always disable btest server on target when done (success or failure)
+    if (serverClient) {
+      try {
+        await serverClient.connect();
+        await serverClient.execute('/tool/bandwidth-server/set', { enabled: 'no' });
+        serverClient.disconnect();
+      } catch {
+        // Best-effort — don't mask the original error
+      }
+    }
   }
 });
 
diff --git a/frontend/src/components/device-detail/ToolsTab.tsx b/frontend/src/components/device-detail/ToolsTab.tsx
index e30c139..7d8c915 100644
--- a/frontend/src/components/device-detail/ToolsTab.tsx
+++ b/frontend/src/components/device-detail/ToolsTab.tsx
@@ -473,19 +473,35 @@ function PacketCaptureTool({ deviceId, interfaces }: { deviceId: number; interfa
 // ─── Bandwidth Test ───────────────────────────────────────────────────────────
 
 function BandwidthTestTool({ deviceId }: { deviceId: number }) {
-  const [address, setAddress] = useState('');
+  // 'managed' = pick a device from inventory; 'manual' = type an IP (server must be pre-enabled)
+  const [mode, setMode] = useState<'managed' | 'manual'>('managed');
+  const [targetDeviceId, setTargetDeviceId] = useState('');
+  const [manualAddress, setManualAddress] = useState('');
   const [direction, setDirection] = useState('both');
   const [duration, setDuration] = useState('5');
   const [protocol, setProtocol] = useState('tcp');
   const [loading, setLoading] = useState(false);
   const [error, setError] = useState('');
-  const [result, setResult] = useState<{ tx_mbps: number; rx_mbps: number; direction: string; protocol: string; duration: number } | null>(null);
+  const [result, setResult] = useState<{ tx_mbps: number; rx_mbps: number; direction: string; protocol: string; duration: number; target_ip: string } | null>(null);
+
+  const { data: allDevices = [] } = useQuery({
+    queryKey: ['devices'],
+    queryFn: () => devicesApi.list().then((r) => r.data),
+  });
+
+  // Exclude the current device from the target list
+  const targetDevices = allDevices.filter((d: { id: number; status?: string }) => d.id !== deviceId);
+
+  const canRun = mode === 'managed' ? !!targetDeviceId : !!manualAddress.trim();
 
   const run = async () => {
-    if (!address) return;
+    if (!canRun) return;
     setLoading(true); setError(''); setResult(null);
     try {
-      const { data } = await deviceToolsApi.btest(deviceId, { address, direction, duration: parseInt(duration), protocol });
+      const body = mode === 'managed'
+        ? { target_device_id: parseInt(targetDeviceId), direction, duration: parseInt(duration), protocol }
+        : { address: manualAddress.trim(), direction, duration: parseInt(duration), protocol };
+      const { data } = await deviceToolsApi.btest(deviceId, body);
       setResult(data);
     } catch (e: unknown) {
       const msg = (e as { response?: { data?: { error?: string } } })?.response?.data?.error;
@@ -498,17 +514,49 @@ function BandwidthTestTool({ deviceId }: { deviceId: number }) {
   return (
     <div className="space-y-4">
       <p className="text-xs text-gray-500 dark:text-slate-400">
-        Runs RouterOS /tool/bandwidth-test to measure throughput between this device and a target IP.
-        The target must have the bandwidth-test server enabled.
+        Measures throughput between this device (client) and a target (server). When targeting a managed
+        device, the bandwidth-test server is automatically enabled and disabled for you.
       </p>
+
+      {/* Mode toggle */}
+      <div className="flex gap-2">
+        <button
+          onClick={() => setMode('managed')}
+          className={clsx('px-3 py-1 rounded text-xs font-medium border transition-colors', mode === 'managed'
+            ? 'bg-blue-600 text-white border-blue-600'
+            : 'border-gray-300 dark:border-slate-600 text-gray-600 dark:text-slate-300 hover:border-blue-400')}
+        >
+          Managed device
+        </button>
+        <button
+          onClick={() => setMode('manual')}
+          className={clsx('px-3 py-1 rounded text-xs font-medium border transition-colors', mode === 'manual'
+            ? 'bg-blue-600 text-white border-blue-600'
+            : 'border-gray-300 dark:border-slate-600 text-gray-600 dark:text-slate-300 hover:border-blue-400')}
+        >
+          Manual IP
+        </button>
+      </div>
+
       <div className="flex flex-wrap gap-3">
-        <input
-          className="input flex-1 min-w-48"
-          placeholder="Target IP address"
-          value={address}
-          onChange={(e) => setAddress(e.target.value)}
-          onKeyDown={(e) => e.key === 'Enter' && run()}
-        />
+        {mode === 'managed' ? (
+          <select className="input flex-1 min-w-48" value={targetDeviceId} onChange={(e) => setTargetDeviceId(e.target.value)}>
+            <option value="">— Select target device —</option>
+            {targetDevices.map((d: { id: number; name: string; ip_address: string; status?: string }) => (
+              <option key={d.id} value={d.id}>
+                {d.name} ({d.ip_address}){d.status === 'offline' ? ' — offline' : ''}
+              </option>
+            ))}
+          </select>
+        ) : (
+          <input
+            className="input flex-1 min-w-48"
+            placeholder="Target IP address"
+            value={manualAddress}
+            onChange={(e) => setManualAddress(e.target.value)}
+            onKeyDown={(e) => e.key === 'Enter' && run()}
+          />
+        )}
         <select className="input w-32" value={direction} onChange={(e) => setDirection(e.target.value)}>
           <option value="both">Both</option>
           <option value="receive">Receive</option>
@@ -523,6 +571,13 @@ function BandwidthTestTool({ deviceId }: { deviceId: number }) {
         </select>
         <RunButton loading={loading} onClick={run} label="Test" />
       </div>
+
+      {mode === 'manual' && (
+        <p className="text-xs text-amber-600 dark:text-amber-400">
+          Manual mode: ensure the bandwidth-test server is running on the target device before starting.
+        </p>
+      )}
+
       {loading && (
         <p className="text-sm text-gray-500 dark:text-slate-400">
           Running {duration}s bandwidth test — please wait…
@@ -534,13 +589,13 @@ function BandwidthTestTool({ deviceId }: { deviceId: number }) {
           {(result.direction === 'both' || result.direction === 'transmit') && (
             <div className="p-4 bg-blue-50 dark:bg-blue-900/20 border border-blue-200 dark:border-blue-800 rounded-lg text-center">
               <div className="text-2xl font-bold text-blue-700 dark:text-blue-300">{result.tx_mbps} Mbps</div>
-              <div className="text-xs text-blue-500 dark:text-blue-400 mt-1">TX (Upload)</div>
+              <div className="text-xs text-blue-500 dark:text-blue-400 mt-1">TX (Upload to {result.target_ip})</div>
             </div>
           )}
           {(result.direction === 'both' || result.direction === 'receive') && (
             <div className="p-4 bg-green-50 dark:bg-green-900/20 border border-green-200 dark:border-green-800 rounded-lg text-center">
               <div className="text-2xl font-bold text-green-700 dark:text-green-300">{result.rx_mbps} Mbps</div>
-              <div className="text-xs text-green-500 dark:text-green-400 mt-1">RX (Download)</div>
+              <div className="text-xs text-green-500 dark:text-green-400 mt-1">RX (Download from {result.target_ip})</div>
             </div>
           )}
           <div className="col-span-2 text-xs text-gray-500 dark:text-slate-400 text-center">
diff --git a/frontend/src/services/api.ts b/frontend/src/services/api.ts
index 9b63454..6ed9310 100644
--- a/frontend/src/services/api.ts
+++ b/frontend/src/services/api.ts
@@ -337,9 +337,9 @@ export const deviceToolsApi = {
     api.post<{ success: boolean; message: string }>(`/devices/${id}/tools/wol`, body, { timeout: TOOL_TIMEOUT }),
   capture: (id: number, body: { interface?: string; filter_ip?: string; duration?: number }) =>
     api.post(`/devices/${id}/tools/capture`, body, { timeout: 120_000, responseType: 'blob' }),
-  btest: (id: number, body: { address: string; direction?: string; duration?: number; protocol?: string }) =>
-    api.post<{ tx_mbps: number; rx_mbps: number; direction: string; protocol: string; duration: number; raw: Record<string, string> | null }>(
-      `/devices/${id}/tools/btest`, body, { timeout: 60_000 }
+  btest: (id: number, body: { target_device_id?: number; address?: string; direction?: string; duration?: number; protocol?: string }) =>
+    api.post<{ tx_mbps: number; rx_mbps: number; direction: string; protocol: string; duration: number; target_ip: string; raw: Record<string, string> | null }>(
+      `/devices/${id}/tools/btest`, body, { timeout: 75_000 }
     ),
 };