python - 绑定(bind)到特定范围内的开放端口

Question

我想绑定(bind)一个套接字来监听一定范围内的任何开放端口。通常我绑定(bind)到零，操作系统很适合给我一个随机的开放端口。但是现在我需要保持在某个范围内，例如 4000-5000由防火墙指定。我如何向操作系统询问此范围内的开放端口？

我是从 Python 做的。我对跨平台解决方案感兴趣，但会满足于特定于 Linux 的东西。

Answer 1

我曾经为了完全相同的目的写了一小段代码

# SWAMI KARUPPASWAMI THUNNAI
import socket

class Ports:
    """
    This class is ued to find all the open ports present
    """
    __upper_bound = 0
    __lower_bound = 0
    __ip = "127.0.0.1" # change your i.p if it is not your machine IP
    __ports = [] # our actively available ports
    # used to set upper and lower bounds i.e the range of the ports to be scanned
    def __init__(self,initial,final):
        self.__lower_bound=initial
        self.__upper_bound=final

    # a method which scans for the range of ports
    def scan_for_ports(self):
        for i in range(self.__lower_bound,self.__upper_bound):
            print("[SCANNING]: "+str(i))
            check = self.is_port_opened(i)
            if check == 0:
                self.__ports.append(i) # append our opened port no
    # a method to find whether a port is opened
    def is_port_opened(self,portNo):
        try:
            client = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
            connection = client.connect_ex((self.__ip,portNo)) # remember it is a tuple
            port_opened = connection
            client.close()
            print(port_opened)
            return port_opened
        except socket.error as e:
            print("SOCKET CANNOT BE CREATED! Do you have admin previlidges? or the port may be closed!")
            print(e)
            return -1
        return -1
    # A method to get the list of open ports
    def get_list(self):
        for i in self.__ports:
            print("OPENED: "+str(i))


if __name__=="__main__":
    ports = Ports(75,81)
    ports.scan_for_ports()
    ports.get_list()

现在，您可以轻松编写一个客户端来监听特定端口。我已经在我的计算机上使用一个小的 python 脚本打开了一个端口 (80) 进行了几分钟的测试，结果很好，请参见这里!