In the following example, the server is listening on a default port, and by following a TCP/IP connection, the client sends to the server the date and time that the connection was established.

Here is the server implementation for server.py:

1. Import the relevant Python modules:

import socket
import time

2. Create a new socket using the given address, socket type, and protocol number:

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

3. Get the local machine name (host):

host=socket.gethostname()

4. Set the port number:

port=9999

5. Connect (bind) the socket to host and to port:

serversocket.bind((host,port))

6. Listen for connections made to the socket. The argument of 5 specifies the maximum number of connections in the queue. The maximum value depends on the system (usually, it is 5) and the minimum value is always 0:

serversocket.listen(5)

7. Establish a connection:

while True:

8. Then, the connection is accepted. The return value is a pair (conn, address), where conn is a new socket object that is used to send and receive data, and address is the address linked to the socket. Once accepted, a new socket is created and it will have its own identifier. This new socket is only used with this particular client:

clientsocket,addr=serversocket.accept()

9. The address and the port that is connected are printed out:

print ("Connected with[addr],[port]%s"%str(addr))

10. currentTime is evaluated:

currentTime=time.ctime(time.time())+"
"

11. The following statement sends data to the socket, returning the number of bytes sent:

clientsocket.send(currentTime.encode('ascii'))

12. The following statement indicates the socket closure (that is, the communication channel); all subsequent operations on the socket will fail. The sockets are automatically closed when they are rejected, but it is always recommended to close them with the close() operation:

clientsocket.close()

The code for the client (client.py) is as follows:

1. Import the socket library:

import socket

2. The socket object is then created:

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

3. Get the local machine name (host):

host=socket.gethostname()

4. Set the port number:

port=9999

5. Set up the connection to host and port:

s.connect((host,port))

6. Now, close the connection and finally print out the connection time to the server:

s.close()
print ("Time connection server:%s"%tm.decode('ascii'))