Simple Mail Transport Protocol

http://www.csie.nctu.edu.tw/document/CIE/Topics/94.htm

The EMail protocol involved in sending messages (typically from sending-user to sender's server to recipient's server).

• article on mimicing via TelNet - good for testing servers - oops that has disappeared

• http://www.activexperts.com/activemail/telnet/

• http://www.yuki-onna.co.uk/email/smtp.html

A server which uses SMTP is typically called a [Mail Transport Agent] (MTA).

There are a number of Open Source MTA apps ([Send Mail], [PostFix], [QMail], [ExIm]). This piece provides a very short comparison.

[VERP]: [Variable Envelope Return Path]

• to make it easier to track bounce messages associated with forwarded emails

• http://cr.yp.to/proto/verp.txt

• [PostFix] http://www.postfix.org/VERP_README.html

• http://en.wikipedia.org/wiki/Variable_envelope_return_path

The protocols associated with reading EMail are POP and IMAP.

notes on writing code to send messages

get better performance from holding single SMTP connection object for multiple messages sent

• but if a send fails (because of bad address or something) the connection often gets hosed (e.g. your next send gets a nested command error or something like that)

  • so typically call quit on the connection

  • so have to re-create a connection or the next send in the batch will fail

  • or is there a reset function I could use instead of quit?

    • there's a low-level RSET command, but will avoid for now

• conclusion: just use a separate connection per message for now (I would welcome input from a PyThon guru...)

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