Using nmap library in Python program

Question

I have a simple Python program which uses nmap library to do port scanning.

from optparse import OptionParser
import nmap 
from threading import * 
screenLock=Semaphore(value=1)
def nmapScan(thost,tport):
 x=nmap.PortScanner()
 x.scan(thost,tport)
 state=x[thost]['tcp'][int(tport)]['state']
 print "[*]" + thost + "tcp/"+tport+" "+state
def main():
 parser=OptionParser('usage %prog -H <target host> -p <target port>')
 parser.add_option('-H',dest='thost',type='string',help='specify target host')
 parser.add_option('-p',dest='tports',type='string',help='specify target port[s] seperated by comma')
 (options,args)=parser.parse_args()
 thost=options.thost
 tports=options.tports
 tports=tports.split(',')
 if (thost==None)|(tports==None):
 print parser.usage
 exit(0)
 for i in tports:
 nmapScan(thost,i)
main()

When i run the program, i get the following error.

akshayrajmacbookpro$ python nmapScanner.py -H 192.168.1.60 -p 80,443
Traceback (most recent call last):
 File "nmapScanner.py", line 28, in <module>
main()
File "nmapScanner.py", line 26, in main
nmapScan(thost,i)
File "nmapScanner.py", line 10, in nmapScan
state=x[thost]['tcp'][int(tport)]['state']
File "build/bdist.macosx-10.11-intel/egg/nmap/nmap.py", line 555, in __getitem__
KeyError: '192.168.1.60'

I tried using url instead of ip in the command line. But I get the same error. Being new to Python, I am not able to understand and resolve this.

• fips: What do you expect state to have?

Answer 1

x (instance of nmap.PortScanner) does not contain those keys. To be able to iterate the scan results you can do this:

for host, result in x._scan_result['scan'].items():
 print "[*]" + thost + "tcp/" + tport + " " + result['status']['state']

It's best if you looked at the docs or source code of python-nmap to see what other useful info is available e.g. Service name and version that is listening on that port.

More info here: https://bitbucket.org/xael/python-nmap/src/f368486a2cf12ce2bf3d5978614586e89c49c417/nmap/nmap.py?at=default&fileviewer=file-view-default#nmap.py-381

• Akshay: But according to the documentation at pypi.python.org/pypi/python-nmap, my syntax is correct @fips
• fips: You are right, it seems both options should work. Actually when you do x[host] it accesses _scan_result['scan'] internally which is essentially the same thing. So you were getting a key error because that host did not exist in the result. Here is the line that attempts to get the specified host results: bitbucket.org/xael/python-nmap/src/… Maybe you can check before accessing it using if host in x.all_hosts().

Answer 2

The host does not exist in the result of the scan as a "Key" for the Dictionary that forms a part of the data thrown up by scan data. That is probably, in my opinion, the reason for the error. Thanks