feat: configurable DSN (#36988)

* feat: configurable `DSN`

* chore: validate dsn support on save

* fix: DSN validation

frappe/email/doctype/email_account/email_account.json

@@ -78,6 +78,7 @@
   "smtp_port",
   "column_break_38",
   "no_smtp_authentication",
+  "dsn_notify_type",
   "always_bcc",
   "signature_section",
   "add_signature",
@@ -754,13 +755,20 @@
    "ignore_xss_filter": 1,
    "label": "Reply-To Addresses",
    "options": "Reply To Address"
+  },
+  {
+   "description": "Select which delivery events should trigger a delivery status notification (DSN) from the SMTP server.",
+   "fieldname": "dsn_notify_type",
+   "fieldtype": "Select",
+   "label": "Delivery Status Notification Type",
+   "options": "\nSUCCESS\nFAILURE\nDELAY\nSUCCESS,FAILURE\nSUCCESS,FAILURE,DELAY\nNEVER"
   }
  ],
  "icon": "fa fa-inbox",
  "index_web_pages_for_search": 1,
  "links": [],
  "make_attachments_public": 1,
- "modified": "2026-02-06 11:39:39.412130",
+ "modified": "2026-02-11 16:18:15.572240",
  "modified_by": "Administrator",
  "module": "Email",
  "name": "Email Account",

frappe/email/doctype/email_account/email_account.py

@@ -84,6 +84,9 @@ class EmailAccount(Document):
 		default_incoming: DF.Check
 		default_outgoing: DF.Check
 		domain: DF.Link | None
+		dsn_notify_type: DF.Literal[
+			"SUCCESS", "FAILURE", "DELAY", "SUCCESS,FAILURE", "SUCCESS,FAILURE,DELAY", "NEVER"
+		]
 		email_account_name: DF.Data | None
 		email_id: DF.Data
 		email_server: DF.Data | None
@@ -220,7 +223,8 @@ class EmailAccount(Document):
 			frappe.throw(_("SMTP Server is required"))
 
 		self.flags.validate_smtp_connection = True
-		self.get_smtp_server().session
+		session = self.get_smtp_server().session
+		self.validate_dsn(session)
 		del self._smtp_server_instance
 
 	def validate_reply_to_addresses(self) -> None:
@@ -229,6 +233,18 @@ class EmailAccount(Document):
 				frappe.throw(_("Reply To email is required"))
 			validate_email_address(reply_to.email, True)
 
+	def validate_dsn(self, smtp_session) -> None:
+		"""Validate if the configured SMTP server supports DSN (Delivery Status Notification)."""
+
+		if not self.dsn_notify_type:
+			return
+
+		if not smtp_session.has_extn("DSN"):
+			self.dsn_notify_type = None
+			frappe.msgprint(
+				_("The configured SMTP server does not support DSN (Delivery Status Notification).")
+			)
+
 	def before_save(self):
 		messages = []
 		as_list = 1

frappe/email/doctype/email_queue/email_queue.py

@@ -196,10 +196,20 @@ class EmailQueue(Document):
 							is_newsletter=is_newsletter,
 						)
 					else:
+						mail_options = []
+						rcpt_options = []
+
+						if ctx.smtp_server.session.has_extn("DSN"):
+							if dsn_notify_type := ctx.email_account_doc.dsn_notify_type:
+								mail_options = ["RET=FULL", f"ENVID={self.name}"]
+								rcpt_options = [f"NOTIFY={dsn_notify_type}"]
+
 						ctx.smtp_server.session.sendmail(
 							from_addr=self.sender,
 							to_addrs=recipient.recipient,
 							msg=message.decode("utf-8").encode(),
+							mail_options=mail_options,
+							rcpt_options=rcpt_options,
 						)
 
 				ctx.update_recipient_status_to_sent(recipient)

frappe/email/smtp.py

@@ -92,6 +92,9 @@ class SMTPServer:
 				if res[0] != 235:
 					frappe.msgprint(res[1], raise_exception=frappe.OutgoingEmailError)
 
+			# Re-issue EHLO after AUTH to refresh server capabilities
+			_session.ehlo()
+
 			self._session = _session
 			self._enqueue_connection_closure()
 			return self._session