checkresolvers.py 文件源码

def check_for_wildcards(args, server, name, rectype, tries=4):
    """
    Verify that the DNS server doesn't return wildcard results for domains
    which don't exist, it should correctly return NXDOMAIN.
    """
    resolver = Resolver()
    resolver.timeout = args.timeout
    resolver.lifetime = args.timeout
    resolver.nameservers = [server]
    nx_names = [base64.b32encode(
                    os.urandom(
                        random.randint(8, 10))
                ).strip('=').lower() + name
                for _ in range(0, tries)]
    correct_result_count = 0
    for check_nx_name in nx_names:
        try:
            result = resolver.query(check_nx_name, rectype)            
            return False  # Any valid response = immediate fail!
        except (NXDOMAIN, NoNameservers):
            correct_result_count += 1
        except DNSException:
            continue        
    return correct_result_count > (tries / 2.0)