Python TCP port scanner

Question

I'm trying to create a TCP port scanner in Python that accepts a number of arguments (-all (displays all ports, both open and closed for the target), -open (only displays the open ports on the target), -target (specify target IP, subnet or hostname) and -range (specify port range).

Currently I've only managed to code the options used in the program, my code is as follows:

import optparse
parser = optparse.OptionParser()
parser.add_option('-all', dest='allPorts', help='displays all ports regardless of status')
parser.add_option('-open', dest='openPorts', help='displays only open ports')
parser.add_option('-target', type='string', dest='targetIP', help='specify target IP address, subnet or hostname')
parser.add_option('-range', type='string', dest='portRange', help='specify port range')
(options, args) = parser.parse_args()

I'm unsure how to continue with the program, particularly with the -all / -open options, any help would be greatly appreciated.

• SomethingSomething: start with getting a filtered sub-list, containing all words for which the condition 'e' not in word is true. Then, you'll need to do some Cartesian multiplication of this list. You'll have N^3 possible strings, where N is number of words after filtering
• SomethingSomething: I think the most intuitive way to implemented is to use 3 nested for loops that all run on your filtered words, then just concatenate them and make the "find-replace" operations
• mata: When trying to crack (brute force) a password taking three random words from your file won't be of much use, you systematically need to try all possible combinations. Also is randomwords.txt the file with the story? If so, you should start by creating a set of candidate words (no duplicates, no words containing e, replace o)

Answer 1

Normally you use str.join to build a new string from several different strings:

''.join(data[:3])

and to replace o with 0 use str.replace:

''.join(data[:3]).replace('o', '0')

Note that you can get 3 samples with random.sample(data, 3), you don't need to shuffle the complete data:

''.join(random.sample(data, 3)).replace('o', '0')

To exclude words containing "e" you can only keep words that do not contain "e" in the input:

with open('randomwords.txt', 'r') as f:
 # a conditional list comprehension
 data = [word for word in f.read().split() if "e" not in word]
[...]

Answer 2

Try this:

"{}{}{}".format(w1,w2,w3).replace("o","0")

Answer 3

I have modified one answer posted here, Actually i wanted to edit that answer but deleted by the author.
Try Following:

res = ""
for x in data[:3]:
 res += x
 res.replace("o", "0")
print res

OR

res = ""
for x in data[:3]:
 res = res + x
print res.replace("o", "0")

Try Last one.

Answer 4

First, your assignement seems to allow repetitions (e.g. passwords like "passw0rdpassw0rdpassw0rd") while your method doesn't. It is also inefficient. You can use random.choice three times instead.

Concatenation of strings is done with + operator, e.g. concatenation = str1 + str2 + str3, or join function. Replacing o with 0 is done with string class method replace, e.g. concatenation.replace('o', '0').