Question

Skeleton Python Code for the Mail Client

from socket import *

msg =”\r\n I love computer networks!”

endmsg = ”\r\n.\r\n”

# Choose a mail server (e.g. Google mail server) and call it mailserver

mailserver = #Fill in start #Fill in end

# Create socket called clientSocket and establish a TCP connection with mailserver

#Fill in start

#Fill in end

recv = clientSocket.recv(1024)

print recv

if recv[:3] != '220':

print '220 reply not received from server.'

# Send HELO command and print server response.

heloCommand = 'HELO Alice\r\n' clientSocket.send(heloCommand) recv1 = clientSocket.recv(1024)

print recv1

if recv1[:3]! = '250':

print '250 reply not received from server.'

# Send MAIL FROM command and print server response.

# Fill in start

# Fill in end

# Send RCPT TO command and print server response.

# Fill in start

# Fill in end

# Send DATA command and print server response.

# Fill in start

# Fill in end #

Send message data.

# Fill in start

# Fill in end

# Message ends with a single period.

# Fill in start

# Fill in end

# Send QUIT command and get server response.

# Fill in start

# Fill in end

1. Mail servers like Google mail (address: smtp.g mail.com, port: 587) requires your client to add a Transport Layer Security (TLS) or Secure Sockets Layer (SSL) for authentication and security reasons, before you send MAIL FROM command. Add TLS/SSL commands to your existing ones and implement your client using Google mail server at above address and port

Answer 1

Code:

#serverAddress: address of serverAddress. I have set it to "localhost", you can change it suit your needs.

#portNumber: portNumber on which software is running

#sendersEmailAddress: email address from which email is sent.

#receiversEmailAddress: email address to which email is ent

from socket import *

msg = "\r\n I love computer networks!"

endmsg = "\r\n.\r\n"

serverAddress = "localhost"

portNumber = 25

sendersEmailAddress = "[email protected]"

receiversEmailAddress = "[email protected]"

# Connect to the local host (an EECS serverAddress, where this code should be executed)

mailServer = (serverAddress, portNumber)

# Create socket called clientSocket and establish a TCP connection with nailserverAddress

#Fill in start

clientSocket = socket(AF_INET, SOCK_STREAM)

clientSocket.connect(mailServer)

#Fill in end

recv = clientSocket.recv(1024).decode()

print(recv)

if recv[:3] != '220':

print('220 reply not received from serverAddress.')

# Send HELO command and print serverAddress response.

heloCommand = 'HELO Alice\r\n'

clientSocket.send(heloCommand.encode())

recv1 = clientSocket.recv(1024).decode()

print(recv1)

if recv1[:3] != '250':

print('250 reply not received from serverAddress.')

# Send MAIL FROM command and print serverAddress response.

# Fill in start

fromCommand = 'MAIL FROM: ' + sendersEmailAddress + '\r\n'

clientSocket.send(fromCommand.encode())

recv2 = clientSocket.recv(1024).decode()

print(recv2)

# Fill in end

# Send RCPT TO command and print serverAddress response.

# Fill in start

rcptCommand = 'RCPT TO: ' + receiversEmailAddress + '\r\n'

clientSocket.send(rcptCommand.encode())

recv3 = clientSocket.recv(1024).decode()

print(recv3)

# Fill in end

# Send DATA command and print serverAddress response.

# Fill in start

dataCommand = 'DATA\r\n'

clientSocket.send(dataCommand.encode())

recv4 = clientSocket.recv(1024).decode()

print(recv4)

# Fill in end

# Send message data.

# Fill in start

clientSocket.send(msg.encode())

# Fill in end

# Message ends with a single period.

# Fill in start

clientSocket.send(endmsg.encode())

recv5 = clientSocket.recv(1024).decode()

print(recv5)

# Fill in end

# Send QUIT command and get serverAddress response.

# Fill in start

quitCommand = 'QUIT\r\n'

clientSocket.send(quitCommand.encode())

recv6 = clientSocket.recv(1024).decode()

print(recv6)

# Fill in end

M #serverAddress: address of serverAddress. I have set it to "localhost", you can change it suit your needs. #portNumber: portNumber on which software is running #sendersEmailAddress: email address from which email is sent. #receivers EmailAddress: email address to which email is ent from socket import Number * OOOI msg = "\r\n I love computer networks!" endmsg = "\r\n\r\n" serverAddress = "localhost" portNumber = 25 senders EmailAddress = "[email protected]" receivers EmailAddress = "[email protected]" # Connect to the local host (an EECS serverAddress, where this code should be executed) mailServer = (serverAddress, portNumber) # Create socket called client Socket and establish a TCP connection with nailserverAddress #Fill in start client Socket = socket (AF INET, SOCK STREAM) client Socket.connect (mailServer) #Fill in end recv = client Socket.recv (1024).decode() print (recv) if recy[:3] != '220': print('220 reply not received from serverAddress.') # Send HELO command and print serverAddress response. heloCommand = 'HELO Alice\r\n' client Socket.send (heloCommand.encode()) recvl = client Socket.recv (1024).decode() print (recvl) if recvl[:3] != "250": print('250 reply not received from serverAddress.') # Send MAIL FROM command and print serverAddress response. # Fill in start fromCommand = 'MAIL FROM: ' + senders EmailAddress + '\r\n' client Socket.send (fromCommand.encode()) recv2 = client Socket.recv (1024).decode() print (recv2) # Fill in end 43 # Send RCPT TO command and print serverAddress response. # Fill in start rcpt Command = 'RCPT TO: ' + receivers EmailAddress + '\r\n' client Socket.send (rcptCommand.encode()) recv3 = client Socket.recv (1024).decode() print (recv3) # Fill in end # Send DATA command and print serverAddress response. # Fill in start dataCommand = 'DATA\r\n' client Socket.send (dataCommand.encode()) recv4 = client Socket.recv (1024).decode() print (recv4) # Fill in end # Send message data. # Fill in start client Socket.send (msg.encode()) # Fill in end 64 # Message ends with a single period. # Fill in start client Socket.send (endmsg.encode()) recv5 = client Socket.recv (1024).decode() print (recv5) # Fill in end # Send QUIT command and get serverAddress response. # Fill in start quitCommand = 'QUIT\r\n' client Socket.send (quitCommand.encode()) recv6 = client Socket.recv (1024).decode() print (recv6) # Fill in end