Watch your network in the background on Android

NetBlade can scan a saved network at regular intervals and notify you about what changed: a device it has never seen, a known device joining or leaving, a camera or a device exposing risky services. This article shows how to turn it on, what triggers each alert, and how to keep it working without draining the battery.

Before you start

A saved network: “LAN” tab → ⋮ → “Name network”. See Get started with NetBlade on Android.
The notification permission on Android 13 or later.
The phone connected to that network. Monitoring only covers the network the phone is on at that moment.
Background monitoring is free.

1. Build a clean baseline

Alerts are about change, so they are only as useful as what NetBlade already knows. Before turning monitoring on:

Switch on the devices you normally use.
Run a full scan from the “LAN” tab.
Personalize the devices you recognise (name, icon, tag), so the alerts later show names you understand.

Tip: Anything you cannot identify at this stage is worth investigating now, not after the first alert. Open its details and try “Identify”, which asks the device for its NetBIOS name, workgroup and web server.

2. Mark the network as monitored

Tap the router icon in the top bar (“Saved networks”) and edit your network, or use “LAN” tab → ⋮ → “Name network”.
Turn on “Monitor this network”.
Save.

Monitoring is per network: alerts only fire for saved networks whose “Monitor this network” switch is on.

3. Turn on background monitoring

Open “Settings” → “Monitoring”.
Turn on “Background monitoring”.
Pick the “Check frequency”: 1, 3, 6, 12 or 24 hours.
If Android asks for the notification permission, allow it. If notifications are off, the app tells you and opens the right system settings.

With only this switch on, each check scans the network and notifies you about new devices, the ones NetBlade has never seen on this network.

Note: When the phone joins a monitored network, NetBlade also runs a check right away, so you do not wait for the next interval.

4. Choose which alerts you want

Under “Settings” → “Monitoring” you can add:

“Presence alerts”: notifies when known devices join or leave. Useful to know when a family member’s phone arrives, or when a server drops off. On a busy network it can be noisy.
“Security alerts”: a high-priority notification when a new device looks like a camera or exposes risky services. Turning this on also turns on background monitoring, because the alerts come from its scan.
“Notify on known network”: a notification each time you connect to a network you have named.
“Quiet hours”: set a “From” and “to” time. Non-critical alerts are silenced during those hours; security alerts still ring.

5. Know what triggers each alert

New device: a device that is not in NetBlade’s list of known devices for this network.
Presence: a known device that was absent and is back, or was present and is gone. Devices you have muted are skipped.
Security alert, camera: on each new device NetBlade probes a set of ports. It flags a camera when it finds RTSP (554) or other ports typical of camera recorders, or when the vendor is a known camera brand such as Hikvision, Dahua, Axis or Reolink.
Security alert, risky device: a new device with high or critical findings in its security assessment, for example exposed Telnet, RDP or databases. The notification names the services.
Host monitor: each check also covers the hosts in “Tools” → “Host monitor”, which notify when a host goes down, comes back, or when its certificate is about to expire.
PC defences: if you use scheduled Windows inventory, NetBlade tells you when antivirus, firewall or encryption goes off, a new administrator appears or a disk is almost full. See Read a Windows PC’s inventory.

If several risky devices appear in one pass, you get one notification that lists them, not one per device.

6. Silence a single device

Some devices come and go all day: a laptop, a TV that sleeps. Open the device’s details and turn on “Mute this device”. It stops producing join and leave notifications, while everything else keeps working.

7. Keep it reliable on battery

Background checks are best-effort. Android may delay or skip them to save battery, and some manufacturers are stricter than others.

Exclude NetBlade from battery optimization in the Android settings. The path varies by manufacturer, usually Settings → Apps → NetBlade → Battery.
Pick a check frequency that fits your need. Every hour catches things sooner; every 6 or 12 hours is gentler on the battery.
Remember that a check needs the phone to be on the monitored network.

Note: If in the background NetBlade cannot tell for sure which saved network you are on, it skips the check rather than record events under the wrong network.

Check that it worked

In “Settings” → “Monitoring” tap “Check now”. It runs a check immediately, or tells you why it cannot: for example, that the network is not saved or not monitored.
Open the ⓘ “My network” icon → “Network timeline”. New devices, arrivals, departures, hosts up and down, and internet lost and restored all appear here.
“Internet monitor”, from the same icon, starts to show uptime once checks run.

If something goes wrong

“Check now” says the network is not saved. Name the network from the “LAN” tab first.
It says the network is saved but not monitored. Turn on “Monitor this network” for that network.
No notifications at all. Check the notification permission and that the “Security alerts” channel is not disabled in Android’s app notification settings.
Alerts arrive hours late. That is Android’s battery management. Exclude NetBlade from battery optimization.
A device keeps showing as new. Some phones and laptops change their private (random) MAC address from time to time, and each change looks like a new device. Setting that device to keep a fixed address on your network makes it stable.

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