Device_tracker platform nmap_tracker not creating new known_device, or device_tracker entities

Configuration
1

I am having trouble with nmap_tracker. I have attempted to narrow this down to a single case with my current configuration, which looks like:

- platform:
  scan_options: " --privileged -sP "
  track_new_devices: yes
  hosts: 192.168.1.2 # Just a single host for testing

I have turned up logging in the logger section:

homeassistant.components.device_tracker: debug

I get the following in my log:

2018-04-24 16:26:17 INFO (MainThread) [homeassistant.components.device_tracker] Setting up device_tracker.nmap_tracker
2018-04-24 16:26:17 INFO (Thread-16) [homeassistant.components.device_tracker.nmap_tracker] Scanner initialized
2018-04-24 16:26:17 INFO (Thread-10) [homeassistant.components.device_tracker.nmap_tracker] Scanning...
2018-04-24 16:26:17 INFO (Thread-10) [homeassistant.components.device_tracker.nmap_tracker] nmap scan successful

However, no new devices appear in known_devices (other device_trackers are not have problems changing the file), and I don’t see any new device_tracker.* entities appearing. What am I missing?

2

Since it says it scanned I assume you installed the dependencies? arp/nmap

Do you have a device with the IP of 192.168.1.2 that is powered on /connected?

What kind of device is at 192.168.1.2? Some devices don’t respond to network scans (Amazon Echo and Nest Thermostats come to mind)

3

The dependencies from that page are installed:

$ sudo apt-get install net-tools nmap
Reading package lists... Done
Building dependency tree
Reading state information... Done
net-tools is already the newest version (1.60+git20161116.90da8a0-1).
nmap is already the newest version (7.40-1).

All dependencies seem to work from the command line without an error. The single device I am testing is a phone, but I changed to an always-connected device to verify…same issue.

Let me understand, though…I had assumed that if the device does not respond, a device_tracker entry indicating “not home” would be created. In other words, the entity is created regardless of connectivity, and the device_tracker state indicates if it’s successful. Is this not the case? Does it have to succeed once to create the entity?

4

I would assume it would need a response at least once. The known_devices.yaml file will be by mac address (for nmap at least) so it will need a response to populate that info.

I would test it with a non mobile device first. At least you can rule that variable out. Set it to scan a computer/laptop that is on and running.

1 Like
5

I had misunderstood, or not thought about the implications of a network scanner (specifically, you cannot create known_devices.yaml entries until you succeed). Since I was testing a single device…I just assumed it would create the entry. Bad assumption! It was a bad ping, and it did create then entry after the first time the device responds. Thanks for getting me back on track.