If you have been given a list of IP addresses of a few machines on your network and you are asked to write a script to find out which hosts are inactive periodically, you would want to create a network scanner type program without installing anything on the target host computers.
This recipe requires installing the Scapy library (> 2.2), which can be obtained at http://www.secdev.org/projects/scapy/files/scapy-latest.zip.
At the time of writing, the default Scapy release works with Python 2, and does not support Python 3. You may download the Scapy for Python 3 from https://pypi.python.org/pypi/scapy-python3/0.20.
We can use Scapy, a mature network-analyzing, third-party library, to launch an ICMP scan. Since we would like to do it periodically, we need Python's sched module to schedule the scanning tasks.
Listing 3.7 shows us how to detect inactive machines, as follows:
#!/usr/bin/env python # Python Network Programming...