Discourage automatic replies to Synapse's emails (#13957)

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>
pull/13992/head
David Robertson 2022-09-30 14:23:37 +01:00 committed by GitHub
parent 4490697b98
commit 5507bfa769
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2 changed files with 14 additions and 0 deletions

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@ -0,0 +1 @@
Ask mail servers receiving emails from Synapse to not send automatic reply (e.g. out-of-office responses).

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@ -187,6 +187,19 @@ class SendEmailHandler:
multipart_msg["To"] = email_address
multipart_msg["Date"] = email.utils.formatdate()
multipart_msg["Message-ID"] = email.utils.make_msgid()
# Discourage automatic responses to Synapse's emails.
# Per RFC 3834, automatic responses should not be sent if the "Auto-Submitted"
# header is present with any value other than "no". See
# https://www.rfc-editor.org/rfc/rfc3834.html#section-5.1
multipart_msg["Auto-Submitted"] = "auto-generated"
# Also include a Microsoft-Exchange specific header:
# https://learn.microsoft.com/en-us/openspecs/exchange_server_protocols/ms-oxcmail/ced68690-498a-4567-9d14-5c01f974d8b1
# which suggests it can take the value "All" to "suppress all auto-replies",
# or a comma separated list of auto-reply classes to suppress.
# The following stack overflow question has a little more context:
# https://stackoverflow.com/a/25324691/5252017
# https://stackoverflow.com/a/61646381/5252017
multipart_msg["X-Auto-Response-Suppress"] = "All"
multipart_msg.attach(text_part)
multipart_msg.attach(html_part)