Implementing Transport Layer Security In Python - Simple Mail Client

I have an assignment to write a simple mail client, and to connect to a google smtp server using sockets (without using smtp lib). However, issuing a MAIL FROM command to a google

Solution 1:

You're connecting to port 587, which is the port for STARTTLS. When using SMTPS (ie. wrapping the socket before any other communication), you need to connect to port 465 instead of port 587. If you use STARTTLS, you wrap the socket later, after using the STARTTLS command and receiving a 220 response to it. After doing STARTTLS, you're supposed to do HELO again, since the server is supposed to forget anything that happened before the STARTTLS.

In either case, the servers at smtp.google.com ports 465 and 587 still won't return a 250 response to the MAIL command, since they require that you are authenticated before you send mail. You'll get a 530 response instead. You'll need to use the AUTH command with your gmail.com credentials to authenticate before you can use MAIL successfully on those servers.

If you don't want to authenticate, and depending on the details of what you need to do, you could try using port 25 of the server found in gmail.com's MX record. At the moment, the server is gmail-smtp-in.l.google.com and supports STARTTLS.

Solution 2:

recv5 = ssl_clientSocket.recv(I1024) 

has a I in the port number, is this causing you the issue? Or have you fixed that part already?