> For the complete documentation index, see [llms.txt](https://wiki.zacheller.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://wiki.zacheller.dev/pentest/courses/beginner-network-pentesting/week-3-python-102/scanner.py.md).

# scanner.py

```python
#!/bin/python3

import sys #system functions and parameters, allows us to enter command line arguments
import socket
from datetime import datetime as dt

#Define our target

if len(sys.argv) == 2:
	target = socket.gethostbyname(sys.argv[1]) #translate a host name to IPV4
else:
	print("Syntax: python3 scanner.py <ip>")
	sys.exit(1)


#Add a pretty banner
print("-" * 50)
print("Scanning target " + target)
print("Time started: "+str(dt.now()))
print("-" * 50)

try:
	for port in range(50,85):
		s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
		socket.setdefaulttimeout(1) #is a float; so as not to hang on a port
		result = s.connect_ex((target,port)) #returns error indicator
		print("Checking port {}".format(port))
		if result == 0:
			print("Port {} is open".format(port))
		s.close()
except KeyboardInterrupt:
	print("\nExiting program.")
	sys.exit()

except socket.gaierror: #cannot connect to hostname
	print("Hostname could not be resolved.")
	sys.exit()

except socket.error:
	print("Couldn't connect to server.")
	sys.exit()

```