2 :mod:`smtplib` --- SMTP protocol client
3 =======================================
6 :synopsis: SMTP protocol client (requires sockets).
7 .. sectionauthor:: Eric S. Raymond <esr@snark.thyrsus.com>
12 single: Simple Mail Transfer Protocol
14 The :mod:`smtplib` module defines an SMTP client session object that can be used
15 to send mail to any Internet machine with an SMTP or ESMTP listener daemon. For
16 details of SMTP and ESMTP operation, consult :rfc:`821` (Simple Mail Transfer
17 Protocol) and :rfc:`1869` (SMTP Service Extensions).
20 .. class:: SMTP([host[, port[, local_hostname[, timeout]]]])
22 A :class:`SMTP` instance encapsulates an SMTP connection. It has methods
23 that support a full repertoire of SMTP and ESMTP operations. If the optional
24 host and port parameters are given, the SMTP :meth:`connect` method is called
25 with those parameters during initialization. An :exc:`SMTPConnectError` is
26 raised if the specified host doesn't respond correctly. The optional
27 *timeout* parameter specifies a timeout in seconds for blocking operations
28 like the connection attempt (if not specified, the global default timeout
29 setting will be used).
31 For normal use, you should only require the initialization/connect,
32 :meth:`sendmail`, and :meth:`quit` methods. An example is included below.
34 .. versionchanged:: 2.6
38 .. class:: SMTP_SSL([host[, port[, local_hostname[, keyfile[, certfile[, timeout]]]]]])
40 A :class:`SMTP_SSL` instance behaves exactly the same as instances of
41 :class:`SMTP`. :class:`SMTP_SSL` should be used for situations where SSL is
42 required from the beginning of the connection and using :meth:`starttls` is
43 not appropriate. If *host* is not specified, the local host is used. If
44 *port* is omitted, the standard SMTP-over-SSL port (465) is used. *keyfile*
45 and *certfile* are also optional, and can contain a PEM formatted private key
46 and certificate chain file for the SSL connection. The optional *timeout*
47 parameter specifies a timeout in seconds for blocking operations like the
48 connection attempt (if not specified, the global default timeout setting
54 .. class:: LMTP([host[, port[, local_hostname]]])
56 The LMTP protocol, which is very similar to ESMTP, is heavily based on the
57 standard SMTP client. It's common to use Unix sockets for LMTP, so our :meth:`connect`
58 method must support that as well as a regular host:port server. To specify a
59 Unix socket, you must use an absolute path for *host*, starting with a '/'.
61 Authentication is supported, using the regular SMTP mechanism. When using a Unix
62 socket, LMTP generally don't support or require any authentication, but your
67 A nice selection of exceptions is defined as well:
70 .. exception:: SMTPException
72 Base exception class for all exceptions raised by this module.
75 .. exception:: SMTPServerDisconnected
77 This exception is raised when the server unexpectedly disconnects, or when an
78 attempt is made to use the :class:`SMTP` instance before connecting it to a
82 .. exception:: SMTPResponseException
84 Base class for all exceptions that include an SMTP error code. These exceptions
85 are generated in some instances when the SMTP server returns an error code. The
86 error code is stored in the :attr:`smtp_code` attribute of the error, and the
87 :attr:`smtp_error` attribute is set to the error message.
90 .. exception:: SMTPSenderRefused
92 Sender address refused. In addition to the attributes set by on all
93 :exc:`SMTPResponseException` exceptions, this sets 'sender' to the string that
94 the SMTP server refused.
97 .. exception:: SMTPRecipientsRefused
99 All recipient addresses refused. The errors for each recipient are accessible
100 through the attribute :attr:`recipients`, which is a dictionary of exactly the
101 same sort as :meth:`SMTP.sendmail` returns.
104 .. exception:: SMTPDataError
106 The SMTP server refused to accept the message data.
109 .. exception:: SMTPConnectError
111 Error occurred during establishment of a connection with the server.
114 .. exception:: SMTPHeloError
116 The server refused our ``HELO`` message.
119 .. exception:: SMTPAuthenticationError
121 SMTP authentication went wrong. Most probably the server didn't accept the
122 username/password combination provided.
127 :rfc:`821` - Simple Mail Transfer Protocol
128 Protocol definition for SMTP. This document covers the model, operating
129 procedure, and protocol details for SMTP.
131 :rfc:`1869` - SMTP Service Extensions
132 Definition of the ESMTP extensions for SMTP. This describes a framework for
133 extending SMTP with new commands, supporting dynamic discovery of the commands
134 provided by the server, and defines a few additional commands.
142 An :class:`SMTP` instance has the following methods:
145 .. method:: SMTP.set_debuglevel(level)
147 Set the debug output level. A true value for *level* results in debug messages
148 for connection and for all messages sent to and received from the server.
151 .. method:: SMTP.connect([host[, port]])
153 Connect to a host on a given port. The defaults are to connect to the local
154 host at the standard SMTP port (25). If the hostname ends with a colon (``':'``)
155 followed by a number, that suffix will be stripped off and the number
156 interpreted as the port number to use. This method is automatically invoked by
157 the constructor if a host is specified during instantiation.
160 .. method:: SMTP.docmd(cmd, [, argstring])
162 Send a command *cmd* to the server. The optional argument *argstring* is simply
163 concatenated to the command, separated by a space.
165 This returns a 2-tuple composed of a numeric response code and the actual
166 response line (multiline responses are joined into one long line.)
168 In normal operation it should not be necessary to call this method explicitly.
169 It is used to implement other methods and may be useful for testing private
172 If the connection to the server is lost while waiting for the reply,
173 :exc:`SMTPServerDisconnected` will be raised.
176 .. method:: SMTP.helo([hostname])
178 Identify yourself to the SMTP server using ``HELO``. The hostname argument
179 defaults to the fully qualified domain name of the local host.
180 The message returned by the server is stored as the :attr:`helo_resp` attribute
183 In normal operation it should not be necessary to call this method explicitly.
184 It will be implicitly called by the :meth:`sendmail` when necessary.
187 .. method:: SMTP.ehlo([hostname])
189 Identify yourself to an ESMTP server using ``EHLO``. The hostname argument
190 defaults to the fully qualified domain name of the local host. Examine the
191 response for ESMTP option and store them for use by :meth:`has_extn`.
192 Also sets several informational attributes: the message returned by
193 the server is stored as the :attr:`ehlo_resp` attribute, :attr:`does_esmtp`
194 is set to true or false depending on whether the server supports ESMTP, and
195 :attr:`esmtp_features` will be a dictionary containing the names of the
196 SMTP service extensions this server supports, and their
199 Unless you wish to use :meth:`has_extn` before sending mail, it should not be
200 necessary to call this method explicitly. It will be implicitly called by
201 :meth:`sendmail` when necessary.
203 .. method:: SMTP.ehlo_or_helo_if_needed()
205 This method call :meth:`ehlo` and or :meth:`helo` if there has been no
206 previous ``EHLO`` or ``HELO`` command this session. It tries ESMTP ``EHLO``
210 The server didn't reply properly to the ``HELO`` greeting.
212 .. versionadded:: 2.6
214 .. method:: SMTP.has_extn(name)
216 Return :const:`True` if *name* is in the set of SMTP service extensions returned
217 by the server, :const:`False` otherwise. Case is ignored.
220 .. method:: SMTP.verify(address)
222 Check the validity of an address on this server using SMTP ``VRFY``. Returns a
223 tuple consisting of code 250 and a full :rfc:`822` address (including human
224 name) if the user address is valid. Otherwise returns an SMTP error code of 400
225 or greater and an error string.
229 Many sites disable SMTP ``VRFY`` in order to foil spammers.
232 .. method:: SMTP.login(user, password)
234 Log in on an SMTP server that requires authentication. The arguments are the
235 username and the password to authenticate with. If there has been no previous
236 ``EHLO`` or ``HELO`` command this session, this method tries ESMTP ``EHLO``
237 first. This method will return normally if the authentication was successful, or
238 may raise the following exceptions:
241 The server didn't reply properly to the ``HELO`` greeting.
243 :exc:`SMTPAuthenticationError`
244 The server didn't accept the username/password combination.
247 No suitable authentication method was found.
250 .. method:: SMTP.starttls([keyfile[, certfile]])
252 Put the SMTP connection in TLS (Transport Layer Security) mode. All SMTP
253 commands that follow will be encrypted. You should then call :meth:`ehlo`
256 If *keyfile* and *certfile* are provided, these are passed to the :mod:`socket`
257 module's :func:`ssl` function.
259 If there has been no previous ``EHLO`` or ``HELO`` command this session,
260 this method tries ESMTP ``EHLO`` first.
262 .. versionchanged:: 2.6
265 The server didn't reply properly to the ``HELO`` greeting.
268 The server does not support the STARTTLS extension.
270 .. versionchanged:: 2.6
273 SSL/TLS support is not available to your Python interpreter.
276 .. method:: SMTP.sendmail(from_addr, to_addrs, msg[, mail_options, rcpt_options])
278 Send mail. The required arguments are an :rfc:`822` from-address string, a list
279 of :rfc:`822` to-address strings (a bare string will be treated as a list with 1
280 address), and a message string. The caller may pass a list of ESMTP options
281 (such as ``8bitmime``) to be used in ``MAIL FROM`` commands as *mail_options*.
282 ESMTP options (such as ``DSN`` commands) that should be used with all ``RCPT``
283 commands can be passed as *rcpt_options*. (If you need to use different ESMTP
284 options to different recipients you have to use the low-level methods such as
285 :meth:`mail`, :meth:`rcpt` and :meth:`data` to send the message.)
289 The *from_addr* and *to_addrs* parameters are used to construct the message
290 envelope used by the transport agents. The :class:`SMTP` does not modify the
291 message headers in any way.
293 If there has been no previous ``EHLO`` or ``HELO`` command this session, this
294 method tries ESMTP ``EHLO`` first. If the server does ESMTP, message size and
295 each of the specified options will be passed to it (if the option is in the
296 feature set the server advertises). If ``EHLO`` fails, ``HELO`` will be tried
297 and ESMTP options suppressed.
299 This method will return normally if the mail is accepted for at least one
300 recipient. Otherwise it will raise an exception. That is, if this method does
301 not raise an exception, then someone should get your mail. If this method does
302 not raise an exception, it returns a dictionary, with one entry for each
303 recipient that was refused. Each entry contains a tuple of the SMTP error code
304 and the accompanying error message sent by the server.
306 This method may raise the following exceptions:
308 :exc:`SMTPRecipientsRefused`
309 All recipients were refused. Nobody got the mail. The :attr:`recipients`
310 attribute of the exception object is a dictionary with information about the
311 refused recipients (like the one returned when at least one recipient was
315 The server didn't reply properly to the ``HELO`` greeting.
317 :exc:`SMTPSenderRefused`
318 The server didn't accept the *from_addr*.
321 The server replied with an unexpected error code (other than a refusal of a
324 Unless otherwise noted, the connection will be open even after an exception is
328 .. method:: SMTP.quit()
330 Terminate the SMTP session and close the connection. Return the result of
331 the SMTP ``QUIT`` command.
333 .. versionchanged:: 2.6
337 Low-level methods corresponding to the standard SMTP/ESMTP commands ``HELP``,
338 ``RSET``, ``NOOP``, ``MAIL``, ``RCPT``, and ``DATA`` are also supported.
339 Normally these do not need to be called directly, so they are not documented
340 here. For details, consult the module code.
348 This example prompts the user for addresses needed in the message envelope ('To'
349 and 'From' addresses), and the message to be delivered. Note that the headers
350 to be included with the message must be included in the message as entered; this
351 example doesn't do any processing of the :rfc:`822` headers. In particular, the
352 'To' and 'From' addresses must be included in the message headers explicitly. ::
357 return raw_input(prompt).strip()
359 fromaddr = prompt("From: ")
360 toaddrs = prompt("To: ").split()
361 print "Enter message, end with ^D (Unix) or ^Z (Windows):"
363 # Add the From: and To: headers at the start!
364 msg = ("From: %s\r\nTo: %s\r\n\r\n"
365 % (fromaddr, ", ".join(toaddrs)))
375 print "Message length is " + repr(len(msg))
377 server = smtplib.SMTP('localhost')
378 server.set_debuglevel(1)
379 server.sendmail(fromaddr, toaddrs, msg)
384 In general, you will want to use the :mod:`email` package's features to
385 construct an email message, which you can then convert to a string and send
386 via :meth:`sendmail`; see :ref:`email-examples`.