Cookbook

• Discovery
  • What is Discover
  • Ping Sweep

This is a cookbook of solutions for Netdisco.

Discovery

What is Discover

On the Netdisco homepage, if you click the Discover button then Netdisco will queue a backend job to discover the IP or hostname you typed in the box. If you typed an IP prefix (subnet) then one job is queued for each IP in the network.

The button has two drop-down options called Ping Sweep, which works with an IP prefix (subnet). Netdisco first pings each device in the network and only for those responding is a Discover job added to the queue.

Normally, for a single host IP or name, just clicking Discover is enough. The Ping Sweep option works more efficiently for scanning whole networks but of course relies on the devices responding to ICMP Echo (ping)!

If you know that LLDP or CDP are working well in your network, then a single device should be enough to start and Netdisco will discover everything else all by itself. Alternatively if you have a text file with a list of IP addresses then you can provide that to the netdisco-do command-line utility (run perldoc ~netdisco/bin/netdisco-do).

Ping Sweep

Netdisco includes a worker which can ping sweep an IP prefix (subnet) - any devices responding will have a job queued for discovery.

~netdisco/bin/netdisco-do pingsweep -d 192.0.2.0/24 --enqueue

As the default ping timeout is 0.1 seconds, this job will take about 254*0.1=25.4 seconds to complete. Scanning a /16 network takes up to two hours.

To schedule this regularly, say, once a week, add the following config:

schedule:
  pingsweep:
    device: '192.0.2.0/24'
    when:
      wday: 'sun'
      hour: '14'
      min:  '05'

---