SMTP Commands Reference

import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart

def send_email_smtp(
    smtp_host: str,
    smtp_port: int,
    username: str,
    password: str,
    from_addr: str,
    to_addr: str,
    subject: str,
    body: str,
    use_tls: bool = True
) -> bool:
    """Send email using SMTP with manual command flow."""
    try:
        with smtplib.SMTP(smtp_host, smtp_port) as server:
            server.ehlo()  # EHLO command
            if use_tls:
                server.starttls()  # STARTTLS command
                server.ehlo()     # Re-EHLO after TLS
            server.login(username, password)  # AUTH command

            msg = MIMEMultipart()
            msg['From'] = from_addr
            msg['To'] = to_addr
            msg['Subject'] = subject
            msg.attach(MIMEText(body, 'plain'))

            # MAIL FROM, RCPT TO, DATA commands
            server.sendmail(from_addr, to_addr, msg.as_string())
            return True
    except smtplib.SMTPException as e:
        print(f"SMTP Error: {e}")
        return False

# Test SMTP connection manually
def test_smtp_connection(host: str, port: int) -> dict:
    import socket
    try:
        with smtplib.SMTP(host, port, timeout=5) as server:
            banner = server.getwelcome()
            ehlo_resp = server.ehlo()
            return {
                "connected": True,
                "banner": banner.decode(),
                "extensions": list(server.esmtp_features.keys())
            }
    except Exception as e:
        return {"connected": False, "error": str(e)}

result = test_smtp_connection("smtp.gmail.com", 587)
print(result)