bind() method of SSLSocket class in Python

Method Name:

bind

Method Signature:

bind()

Parameters:

None

Return Value:

None

Method Overview:

The bind() method attaches a socket(Remember, the SSLSocket is derived from the socket class) to an available IP address and a port.
The client programs generally do not invoke the bind() method on a socket instance. The reason is the socket will be attached to an ephemeral port when the bind() method is not called.
The clients, contact server programs all the times. Hence, a server socket should be attached to a specific IP address and a port number.

Example:

The Python program below when executed binds an SSLSocket to a specific port and IP.
The client program provided in the Introduction to SSLSocket, can be used to connect to this server.
The server responds by sending a the temperature of a city to the client.

# An example Python program that binds to an IP address and port
# using the bind() method of SSLSocket class
# and listens for incoming connections from clients. To the
# clients, it responds with the current temperature of a city.
# The temperature values are simply random values between average high and
# low values.

import ssl
import socket
import random

# File paths
caCertFile = "./DemoCA.pem"
svrCertFile = "./DemoSvr.pem"
svrCertKeyFile = "./DemoSvr.key"

# IP address and Port number
ipAddress = "127.0.0.1"
portNumber = 15001

# Socket creation
sock = socket.socket()

# SSL context creation
ctx = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)

# To handle self-signed certificates
ctx.verify_flags = ctx.verify_flags & ~ssl.VERIFY_X509_STRICT
ctx.verify_mode = ssl.CERT_REQUIRED

# Load the certificate of the Certificate Authority, with which the
# server will validate the client certificate
ctx.load_verify_locations(caCertFile)

# Load the server certificate
ctx.load_cert_chain(certfile=svrCertFile, keyfile=svrCertKeyFile)

# Create server socket
serverSocket = socket.socket()

# Make an SSLSocket
secureServerSocket = ctx.wrap_socket(serverSocket,
server_side=True)

# Bind the secure socket to a specific IP address and port number
secureServerSocket.bind((ipAddress, portNumber))

# Listen to accept connections
secureServerSocket.listen()
print("Temperature server listening for client requests:")

while(True):
(clientConnection, clientIP) = secureServerSocket.accept()
temp = random.uniform(50, 65)
tempStr = "Temperature in the city is %2.2f"%temp;
encoded = tempStr.encode()
clientConnection.sendall(encoded)
print("Replied to %s with the temperature value %2.2f"%(clientIP, temp))

Output-Server:

Replied to ('127.0.0.1', 51589) with the temperature value 60.22

Output-Client:

X.509 certificate of the server DemoServer:
{'subject': ((('countryName', 'IN'),), (('stateOrProvinceName', 'KA'),), (('localityName', 'BLR'),), (('organizationName', 'DemoServerOrg'),), (('organizationalUnitName', 'DemoServerUnit'),), (('commonName', 'DemoServer'),), (('emailAddress', 'demoserver@demoservertesting.com'),)), 'issuer': ((('countryName', 'IN'),), (('stateOrProvinceName', 'KA'),), (('localityName', 'BLR'),), (('organizationName', 'DemoCAOrg'),), (('organizationalUnitName', 'DemoCAUnit'),), (('commonName', 'localca'),), (('emailAddress', 'localca@localcatest.com'),)), 'version': 1, 'serialNumber': '01', 'notBefore': 'Sep 22 10:44:04 2025 GMT', 'notAfter': 'Sep 22 10:44:04 2026 GMT'}
Secure communication received from server:Temperature in the city is 55.26

Bind() method of SSLSocket class in Python