'Test if the IP string is a hostmask (rather than a netmask).
Args:
ip_str: A string, the potential hostmask.
Returns:
A boolean, True if the IP string is a hostmask.'

def _is_hostmask(self, ip_str):

    parts = [int(x) for x in ip_str.split('.')]
    if (parts[0] < parts[(-1)]):
        return True
    return False
