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Configure sendmail for SMTP relay with your ISP
Note: this setup does not work properly for smtp-server using SASL (e.g. like
sendmail  smtp 
13 hours ago by dusko
Catches mail and serves it through a dream.

MailCatcher runs a super simple SMTP server which catches any message sent to it to display in a web interface. Run mailcatcher, set your favourite app to deliver to smtp:// instead of your default SMTP server, then check out to see the mail that's arrived so far.
mail  smtp  testing  email 
18 hours ago by some_hren
Why STARTTLS? - The difference between using SMTP with STARTTLS and using SMTP over an SSL/TLS socket
As far as I understand service providers of text protocols (e.g. SMTP, LDAP, etc) can secure their protocol communication in one of two ways:

Method 1: Text protocol over a secure socket

You do **not** need explicit support in your client (being it e-mail, LDAP or whatever) to handle this scenario. You can simply wrap the traffic using an external tool such as stunnel (

Method 2: Text protocol with STARTTLS extension

STARTTLS on the other hand is something else. It is an extension to plain text protocols like SMTP that ‘switches’ the connection to a secure SSL/TLS encrypted channel after the initial handshake which happens unsecured. The client and the server starts out unsecured and if they both support the STARTTLS extension then they can switch to using secure connection …. still on the same socket. This allows the server to serve both secure and unsecure connection on the same listening socket.

Confusingly STARTTLS doesn’t actually imply use of TLS; it can just as well be SSL which is used for the encryption of the socket.

As this is an extension to the underlying protocol your client application (as well as the server for that matter) needs to explictly support the STARTTLS extension for this to work. (if e-mail client: must support ‘SMTP with STARTTLS extension‘, if LDAP client: must support ‘LDAP with STARTTLS extension‘, and so on).

What is the problem ?

The amount of documentation in e-mail client applications, SMTP servers, LDAP servers, MTAs (sendmail, postfix) that fail to adequately distinguish between these two methods is amazing!!

Which one to use ?

Both setups provide the same level of security, as far as I know. However officially (at least for protocols like SMTP and LDAP) the method (1) is now deprecated in favour of (2).

I kind of like (1) though because it is something that can be applied without concern for the underlying software. Perhaps I’m just old-fashioned. I don’t see the huge and absolutely must-have reason for why STARTTLS extension was invented. If it was such an important thing to have as part of the text protocol itself then I think the idea would have gone into the HTTP world as well. If HTTP world could live without it why was it so important to get STARTTLS into SMTP, LDAP, etc ? (actually the same thing was attempted in HTTP world via RFC2817 ( but unsurprisingly it has never really been used)

I have a feeling that I’ve either misunderstood something or missed something?
sendmail  mta  mailserver  smtp  ssl 
2 days ago by dusko
python - Sending Multipart html emails which contain embedded images - Stack Overflow
# Send an HTML email with an embedded image and a plain text message for
# email clients that don't want to display the HTML.

from email.MIMEMultipart import MIMEMultipart
from email.MIMEText import MIMEText
from email.MIMEImage import MIMEImage

# Define these once; use them twice!
strFrom = ''
strTo = ''

# Create the root message and fill in the from, to, and subject headers
msgRoot = MIMEMultipart('related')
msgRoot['Subject'] = 'test message'
msgRoot['From'] = strFrom
msgRoot['To'] = strTo
msgRoot.preamble = 'This is a multi-part message in MIME format.'

# Encapsulate the plain and HTML versions of the message body in an
# 'alternative' part, so message agents can decide which they want to display.
msgAlternative = MIMEMultipart('alternative')

msgText = MIMEText('This is the alternative plain text message.')

# We reference the image in the IMG SRC attribute by the ID we give it below
msgText = MIMEText('<b>Some <i>HTML</i> text</b> and an image.<br><img src="cid:image1"><br>Nifty!', 'html')

# This example assumes the image is in the current directory
fp = open('test.jpg', 'rb')
msgImage = MIMEImage(

# Define the image's ID as referenced above
msgImage.add_header('Content-ID', '<image1>')

# Send the email (this example assumes SMTP authentication is required)
import smtplib
smtp = smtplib.SMTP()
smtp.login('exampleuser', 'examplepass')
smtp.sendmail(strFrom, strTo, msgRoot.as_string())
python  email  images  smtp 
2 days ago by ktr
SMTP AUTH in sendmail 8.10-8.13
SMTP AUTH in sendmail 8.10-8.13
Last Update 2006-04-15
sendmail  mta  smtp  ssl  email 
4 days ago by dusko
Configure Sendmail to use Smart Relay
configuration - sendmail: how to configure sendmail on ubuntu? - Stack Overflow
sendmail  mailserver  mta  smtp 
4 days ago by dusko

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