Blackhole

=====

- Added email headers to SIZE checks. Resolves a potential DoS risk.

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- Enable or disable dynamic switches in configuration.

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- Fixed a bug with dynamic switches not being processed.

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- :ref:`dynamic-switches`.
- Re-added the ability to configure max message size. Displays in `EHLO` and
enforced in `DATA` command. Default is 512000 bytes (512 KB).
- Added :ref:`tls_dhparams` options for loading Diffie Hellman ephemeral
parameters.
- Added SMTP AUTH mechanisms. Currently PLAIN, LOGIN and CRAM-MD5 are
supported.
- Added pidfile and related self tests to config_test command.

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No changes in particular except documentation changes. Tag was created
specifically for release to PyPI.

=====

- Added HELP verb that lists all available SMTP verbs. Sending
``HELP <COMMAND>`` will return the syntax for the specified command.

.. code-block::

C: HELP
S: 250 Supported commands: DATA EHLO ETRN HELO...
C: HELP HELO
S: 250 Syntax: HELO domain.tld
C: HELP INVALID
S: 501 Supported commands: DATA EHLO ETRN HELO...

- TLS settings changed based on format taken from
`<https://docs.python.org/3/library/ssl.html#ssl-security>`_.
- TLS 'modern' ciphers enforced, ciphers taken from
`<https://wiki.mozilla.org/Security/Server_Side_TLS>`_.

.. code-block::

0xC0,0x2C - ECDHE-ECDSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AESGCM(256) Mac=AEAD
0xC0,0x30 - ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=RSA Enc=AESGCM(256) Mac=AEAD
0xCC,0x14 - ECDHE-ECDSA-CHACHA20-POLY1305 TLSv1.2 Kx=ECDH Au=ECDSA Enc=ChaCha20(256) Mac=AEAD
0xCC,0x13 - ECDHE-RSA-CHACHA20-POLY1305 TLSv1.2 Kx=ECDH Au=RSA Enc=ChaCha20(256) Mac=AEAD
0xC0,0x2B - ECDHE-ECDSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AESGCM(128) Mac=AEAD
0xC0,0x2F - ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH Au=RSA Enc=AESGCM(128) Mac=AEAD
0xC0,0x24 - ECDHE-ECDSA-AES256-SHA384 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AES(256) Mac=SHA384
0xC0,0x28 - ECDHE-RSA-AES256-SHA384 TLSv1.2 Kx=ECDH Au=RSA Enc=AES(256) Mac=SHA384
0xC0,0x23 - ECDHE-ECDSA-AES128-SHA256 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AES(128) Mac=SHA256
0xC0,0x27 - ECDHE-RSA-AES128-SHA256 TLSv1.2 Kx=ECDH Au=RSA Enc=AES(128) Mac=SHA256