Don't add the bcc header.
See this: http://mail.python.org/pipermail/email-sig/2004-September/000151.html
And this: """Notice that the second argument to sendmail(), the recipients, is passed as a list. You can include any number of addresses in the list to have the message delivered to each of them in turn. Since the envelope information is separate from the message headers, you can even BCC someone by including them in the method argument but not in the message header.""" from http://pymotw.com/2/smtplib
toaddr = '[email protected]'
cc = ['[email protected]','[email protected]']
bcc = ['[email protected]']
fromaddr = '[email protected]'
message_subject = "disturbance in sector 7"
message_text = "Three are dead in an attack in the sewers below sector 7."
message = "From: %s\r\n" % fromaddr
+ "To: %s\r\n" % toaddr
+ "CC: %s\r\n" % ",".join(cc)
# don't add this, otherwise "to and cc" receivers will know who are the bcc receivers
# + "BCC: %s\r\n" % ",".join(bcc)
+ "Subject: %s\r\n" % message_subject
+ "\r\n"
+ message_text
toaddrs = [toaddr] + cc + bcc
server = smtplib.SMTP('smtp.sunnydale.k12.ca.us')
server.set_debuglevel(1)
server.sendmail(fromaddr, toaddrs, message)
server.quit()