Question

我根据python中的套接字指南编写了两个程序。我使用rasbperry pi 3作为客户端，使用常规linux ubuntu计算机作为服务器。这是服务器软件：

import socket
import sys

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

server_address = ('localhost', 15000)
print("starting up on %s port %s" % server_address, file=sys.stderr)
sock.bind(server_address)

# Listen for incoming connections
sock.listen(1)

while True:
    # Wait for a connection
    print("waiting for a connection", file=sys.stderr)
    connection, client_address = sock.accept()

try:
        print("connection from ", client_address, file=sys.stderr)

    # Receive the data in small chunks and retransmit it
    while True:
        data = connection.recv(16)
        print("received %s" % data, file=sys.stderr)
        if data:
            print("sending data back to the client", file=sys.stderr)
            connection.sendall(data)
        else:
            print("no more data from ", client_address, file=sys.stderr)
            break

finally:
        # Clean up the connection
        connection.close()

这是客户端软件：

import socket
import sys

# Create a TCP/IP socket
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

# Connect the socket to the port where the server is listening
server_address = ('192.168.18.250', 15000)
print("connecting to %s port %s" % server_address, file=sys.stderr)
sock.connect(server_address)

try:
# Send data
message = "This is the message.  It will be repeated."
print("sending %s" % message, file=sys.stderr)
sock.sendall(message)

# Look for the response
amount_received = 0
amount_expected = len(message)

while amount_received < amount_expected:
    data = sock.recv(16)
    amount_received += len(data)
    print("received %s" % data, file=sys.stderr)

finally:
    print("closing socket")
    sock.close()

这是服务器上的输出：

peter@GIGAS:~/thermServer$ python3 thermServer.py
starting up on localhost port 15000
waiting for a connection

这是树莓派的输出：

pi@raspberrypi:~ $ python3 thermClient.py
connecting to 192.168.18.250 port 15000
Traceback (most recent call last):
  File "thermClient.py", line 10, in <module>
    sock.connect(server_address)
ConnectionRefusedError: [Errno 111] Connection refused

我已经转发了我的路由器中的端口，但由于这是内部流量无关紧要，我是否错过了在服务器中添加正确打开端口的东西，或者我是否需要在项目之外摆弄一些东西我的linux机器？

Answer 1

在您的服务器代码中：

server_address = ('localhost', 15000)

这在ipnumer 127.0.0.1上设置了一个监听器。这个＆＃39; localhost＆＃39;无法从此服务器外部的客户端联系ip。

如果您希望服务器收听所有已分配的IP地址，请使用：

server_address = ('0.0.0.0', 15000)

Answer 2

当您创建一个绑定到localhost地址的套接字时，您将创建一个侦听＆＃34; loopback接口＆＃34;的套接字，即127.0.0.1。您似乎尝试通过本地IP-192.168.18.250连接到服务器，该IP-192.168.18.250分配给不同的接口（通常是连接到LAN的接口）。因为在该接口上没有任何东西正在侦听端口15000，所以会拒绝连接。

这里有两个解决方案：要么将服务器更改为正在监听正确的接口（听0.0.0.0一般在这里工作，尽管如果它保证静态IP，请改用它）或更改客户端尝试连接到loopback接口 - 尝试连接127.0.0.1或＆＃34; localhost＆＃34;

尝试使用python连接到tcp服务器时拒绝连接

2 个答案: