test_dns.py

#!/usr/bin/env python

import sys, socket, logging

def check_dns(hostname):
    try:
        forward           = socket.gethostbyname(hostname)
        (reverze,_,[ip])  = socket.gethostbyaddr(forward)
        is_ok             = 'yes' if hostname==reverze else 'no'
        return { 'hostname': hostname, 'forward4': forward, 'reverse': reverze, 'status': is_ok }
    except socket.gaierror, e:
        logging.error(e)
        logging.error("Socket error, cannot resolve name or IP, check spelling or ")
        return {}

def check_params(args):
    logging.info("Checking hostname")
    if len(args) == 1:
      logging.info("No hostname has been specified, using localhost")
      print check_dns('localhost')
      sys.exit(0)
    elif len(args) == 2:
      logging.info("Hostname has been specified: " + args[1] )
      print check_dns(args[1])
      sys.exit(0)
    else:
      logging.error("Unknown param")
      sys.exit(2)

def main():
    try:
        logging.basicConfig(level=logging.INFO,
                        format='%(asctime)s %(levelname)-8s %(message)s',
                        datefmt='%a, %d %b %Y %H:%M:%S')
        logging.info('Interpreter location: %s', sys.executable)
        logging.info('sys.argv: ' + str(sys.argv))
        check_params(sys.argv)
    except KeyboardInterrupt:
        logging.info("Ctrl+c was pressed, exiting...")
        sys.exit()

if __name__ == '__main__':
    main()