diff --git a/backend/app/services/task.py b/backend/app/services/task.py
index c7847f9..e55cbe9 100644
--- a/backend/app/services/task.py
+++ b/backend/app/services/task.py
@@ -164,6 +164,32 @@ async def _run_on_device(
                     tr.data = action_data or None
                     tr.duration_ms = duration_ms
 
+        # For ping action: update device status, last_seen, last_ping_ms
+        if action.name == "ping":
+            new_status = "online" if action_result_success else "offline"
+            async with AsyncSessionLocal() as db:
+                async with db.begin():
+                    device_row = await db.get(Device, device.id)
+                    if device_row:
+                        device_row.status = new_status
+                        if action_result_success:
+                            device_row.last_seen = finished_at
+                            ping_ms = (action_data or {}).get("ping_ms")
+                            if ping_ms is not None:
+                                device_row.last_ping_ms = ping_ms
+            await sse_manager.publish(SSEEvent(
+                type="device_status",
+                task_id="__monitor__",
+                data={
+                    "device_id": device.id,
+                    "object_id": device.object_id,
+                    "ip": device.ip,
+                    "status": new_status,
+                    "ping_ms": (action_data or {}).get("ping_ms") if action_result_success else None,
+                    "ts": finished_at.isoformat(),
+                },
+            ))
+
         await sse_manager.publish(SSEEvent(
             type="task_result",
             task_id=task_id,
diff --git a/frontend/src/pages/DeviceDetail.tsx b/frontend/src/pages/DeviceDetail.tsx
index 39c835b..7159e53 100644
--- a/frontend/src/pages/DeviceDetail.tsx
+++ b/frontend/src/pages/DeviceDetail.tsx
@@ -31,6 +31,7 @@ import { useNavigate, useParams } from 'react-router-dom'
 import { useAlerts, useAcknowledgeAlert, useResolveAlert, type AlertItem } from '../api/alerts'
 import { useDevice, useDeleteDevice, useObject } from '../api/objects'
 import { getDeviceWebUrl } from '../utils/deviceUrl'
+import { elapsedAgo } from '../utils/time'
 import { useSnapshots, useSnapshotDiff } from '../api/snapshots'
 import { useDeviceTasks, useTask, type Task } from '../api/tasks'
 import { DeviceEditModal } from '../components/DeviceEditModal'
@@ -463,10 +464,11 @@ export function DeviceDetailPage() {
               <Descriptions.Item label="Статус"><DeviceStatusBadge status={effectiveStatus} /></Descriptions.Item>
               <Descriptions.Item label="Последний ping">
                 {device.last_seen ? (
-                  <Tooltip title={dayjs(device.last_seen).format('DD.MM.YYYY HH:mm:ss')}>
-                    <Space size={4}>
+                  <Tooltip title={elapsedAgo(device.last_seen)}>
+                    <Space size={4} style={{ cursor: 'default' }}>
                       <ClockCircleOutlined style={{ color: '#999' }} />
-                      <span>{effectivePing !== null ? `${effectivePing}мс` : '—'}</span>
+                      <span>{dayjs(device.last_seen).format('DD.MM.YYYY HH:mm:ss')}</span>
+                      {effectivePing !== null && <span style={{ color: '#999' }}>{effectivePing}мс</span>}
                     </Space>
                   </Tooltip>
                 ) : '—'}
diff --git a/frontend/src/pages/WorkObjectDetail.tsx b/frontend/src/pages/WorkObjectDetail.tsx
index b979a04..cc3cc33 100644
--- a/frontend/src/pages/WorkObjectDetail.tsx
+++ b/frontend/src/pages/WorkObjectDetail.tsx
@@ -31,6 +31,7 @@ import { useDevices, useObject, type DeviceItem } from '../api/objects'
 import { useRacks } from '../api/racks'
 import { useActions, useCreateTask, useTask } from '../api/tasks'
 import { CategoryTag, DeviceStatusBadge } from '../components/StatusBadge'
+import { elapsedAgo } from '../utils/time'
 import dayjs from 'dayjs'
 
 function PingButton({
@@ -256,8 +257,11 @@ export function WorkObjectDetailPage() {
         if (row._type === 'group') return null
         const d = row as DeviceRow
         return d.last_seen ? (
-          <Tooltip title={dayjs(d.last_seen).format('DD.MM.YYYY HH:mm:ss')}>
-            <span>{d.last_ping_ms}ms</span>
+          <Tooltip title={elapsedAgo(d.last_seen)}>
+            <span style={{ cursor: 'default' }}>
+              {dayjs(d.last_seen).format('DD.MM.YYYY HH:mm:ss')}
+              {d.last_ping_ms != null ? <span style={{ color: '#999', marginLeft: 4 }}>{d.last_ping_ms}мс</span> : null}
+            </span>
           </Tooltip>
         ) : '—'
       },
diff --git a/frontend/src/utils/time.ts b/frontend/src/utils/time.ts
new file mode 100644
index 0000000..a4a6218
--- /dev/null
+++ b/frontend/src/utils/time.ts
@@ -0,0 +1,17 @@
+/**
+ * Возвращает строку «сколько времени прошло» с момента date до сейчас.
+ * < 60 сек → «N сек назад»
+ * < 60 мин → «N мин назад»
+ * < 24 ч   → «N ч назад»
+ * иначе    → «N д назад»
+ */
+export function elapsedAgo(date: string | Date): string {
+  const diffMs = Date.now() - new Date(date).getTime()
+  const secs = Math.floor(diffMs / 1000)
+  if (secs < 60) return `${secs} сек назад`
+  const mins = Math.floor(secs / 60)
+  if (mins < 60) return `${mins} мин назад`
+  const hours = Math.floor(mins / 60)
+  if (hours < 24) return `${hours} ч назад`
+  return `${Math.floor(hours / 24)} д назад`
+}