diff options
Diffstat (limited to 'synapse/handlers')
| -rw-r--r-- | synapse/handlers/send_email.py | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/synapse/handlers/send_email.py b/synapse/handlers/send_email.py index e2844799e8..804cc6e81e 100644 --- a/synapse/handlers/send_email.py +++ b/synapse/handlers/send_email.py @@ -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) |