Python subprocess nmap output different from terminal command

Question

I'm trying to use the output of nmap command in linux (shell output):

sudo nmap -sn 192.168.1.0/24
------
Nmap scan report for 192.168.1.98
Host is up (0.094s latency).
MAC Address: B8:27:EB:CE:0A:9F (Raspberry Pi Foundation)

In a python script via subprocess:

import subprocess
p = subprocess.Popen(["nmap", "-sn", "192.168.1.0/24"], stdout=subprocess.PIPE)
output, err = p.communicate()
print ("*** Running nmap -sn 192.168.1.0/24 ***\n", output)

Which works pretty well except from the fact that I NEED the MAC line that shell output has and subprocess doesn't.

subprocess output:

\nNmap scan report for 192.168.1.98\nHost is up (0.015s latency).\n

I'm working on an idea of getting IP via MAC/Name and I can't see how to do it without that line...

Answer 1

You don't need to run nmap as a subprocess in python, You can just install the nmap library and import it.

pip install python-nmap

Then write your code:

import json
import nmap

np = nmap.PortScanner()

target = '192.168.1.0/24'

# Scan the subnet 
results = np.scan(hosts=target, arguments='-sn')

# Clean the data nmap returns
results = results['scan']
output = {}
for result in results:
    output[result] = {}
    # Add the MAC addr to the IP
    try:
        output[result]['mac']       = results[result]['addresses']['mac']
    except:
        output[result]['mac']       = 'No MAC address avalible'
    # Add the vendor to the IP
    try:
        output[result]['vendor']    = list(results[result]['vendor'].values())[0]
    except:
        output[result]['vendor']    = 'No vendor info avalible'

print(json.dumps(output,indent=2))

When you run your code you have to run it as sudo or else you wont get the MAC addresses.

Output should look like this

{
  "192.168.1.1": {
    "mac": "16:91:82:xx:xx:xx",
    "vendor": "No vendor info avalible"
  },
  "192.168.1.10": {
    "mac": "44:39:C4:xx:xx:xx",
    "vendor": "Universal Global Scientific Industrial"
  },
  "192.168.1.50": {
    "mac": "No MAC address avalible",
    "vendor": "No vendor info avalible"
  }
}

I hope it was helpful :-)