Local network pinging in python

Question

Does anyone know how to use python to ping a local host to see if it is active or not? We (my team and I) have already tried using

os.system("ping 192.168.1.*") 

But the response for destination unreachable is the same as the response for the host is up.

Thanks for your help.

Answer 1

The best way I could find to do this on Windows, if you don't want to be parsing the output is to use Popen like this:

num = 1
host = "192.168.0.2"
wait = 1000

ping = Popen("ping -n {} -w {} {}".format(num, wait, host),
             stdout=PIPE, stderr=PIPE)  ## if you don't want it to print it out
exit_code = ping.wait()

if exit_code != 0:
    print("Host offline.")
else:
    print("Host online.")  

This works as expected. The exit code gives no false positives. I've tested it in Python 2.7 and 3.4 on Windows 7 and Windows 10.

Answer 2

I've found that using os.system(...) leads to false positives (as the OP said, 'destination host unreachable' == 0).

As stated before, using subprocess.Popen works. For simplicity I recommend doing that followed by parsing the results. You can easily do this like:

if ('unreachable' in output):
        print("Offline")

Just check the various outputs you want to check from ping results. Make a 'this' in 'that' check for it.

Example:

import subprocess

hostname = "10.20.16.30"
output = subprocess.Popen(["ping.exe",hostname],stdout = subprocess.PIPE).communicate()[0]

print(output)

if ('unreachable' in output):
    print("Offline")