Add settings to allow different SMTP envelope from address

custom/conf/app.example.ini

@@ -1450,6 +1450,10 @@ PATH =
 ;; Mail from address, RFC 5322. This can be just an email address, or the `"Name" <email@example.com>` format
 ;FROM =
 ;;
+;; Sometimes it is helpful to use a different address on the envelope. Set USE_DIFFERENT_ENVELOPE_FROM to true to use ENVELOPE_FROM as the from on the envelope
+;USE_DIFFERENT_ENVELOPE_FROM=false
+;ENVELOPE_FROM =
+;;
 ;; Mailer user name and password
 ;; Please Note: Authentication is only supported when the SMTP server communication is encrypted with TLS (this can be via STARTTLS) or `HOST=localhost`.
 ;USER =

docs/content/doc/advanced/config-cheat-sheet.en-us.md

@@ -598,6 +598,8 @@ Define allowed algorithms and their minimum key length (use -1 to disable a type
   - Otherwise if `IS_TLS_ENABLED=false` and the server supports `STARTTLS` this will be used. Thus if `STARTTLS` is preferred you should set `IS_TLS_ENABLED=false`.
 - `FROM`: **\<empty\>**: Mail from address, RFC 5322. This can be just an email address, or
    the "Name" \<email@example.com\> format.
+- `USE_DIFFERENT_ENVELOPE_FROM`: **false**: Set to **true** to use the value of `ENVELOPE_FROM` as the From address on the SMTP mail envelope.
+- `ENVELOPE_FROM`: **\<empty\>**: Address set as the From address on the SMTP mail envelope if `USE_DIFFERENT_ENVELOPE_FROM` is set to true.
 - `USER`: **\<empty\>**: Username of mailing user (usually the sender's e-mail address).
 - `PASSWD`: **\<empty\>**: Password of mailing user.  Use \`your password\` for quoting if you use special characters in the password.
    - Please note: authentication is only supported when the SMTP server communication is encrypted with TLS (this can be via `STARTTLS`) or `HOST=localhost`. See [Email Setup]({{< relref "doc/usage/email-setup.en-us.md" >}}) for more information.

modules/setting/mailer.go

@@ -16,13 +16,15 @@ import (
 // Mailer represents mail service.
 type Mailer struct {
 	// Mailer
-	Name            string
-	From            string
-	FromName        string
-	FromEmail       string
-	SendAsPlainText bool
-	MailerType      string
-	SubjectPrefix   string
+	Name                     string
+	From                     string
+	EnvelopeFrom             string
+	UseDifferentEnvelopeFrom bool
+	FromName                 string
+	FromEmail                string
+	SendAsPlainText          bool
+	MailerType               string
+	SubjectPrefix            string
 
 	// SMTP sender
 	Host              string
@@ -73,6 +75,8 @@ func newMailService() {
 		SendmailTimeout: sec.Key("SENDMAIL_TIMEOUT").MustDuration(5 * time.Minute),
 	}
 	MailService.From = sec.Key("FROM").MustString(MailService.User)
+	MailService.UseDifferentEnvelopeFrom = sec.Key("USE_DIFFERENT_ENVELOPE_FROM").MustBool()
+	MailService.EnvelopeFrom = sec.Key("ENVELOPE_FROM").MustString("")
 
 	if sec.HasKey("ENABLE_HTML_ALTERNATIVE") {
 		log.Warn("ENABLE_HTML_ALTERNATIVE is deprecated, use SEND_AS_PLAIN_TEXT")

services/mailer/mailer.go

@@ -210,8 +210,14 @@ func (s *smtpSender) Send(from string, to []string, msg io.WriterTo) error {
 		}
 	}
 
-	if err = client.Mail(from); err != nil {
-		return fmt.Errorf("Mail: %v", err)
+	if opts.UseDifferentEnvelopeFrom {
+		if err = client.Mail(opts.EnvelopeFrom); err != nil {
+			return fmt.Errorf("Mail: %v", err)
+		}
+	} else {
+		if err = client.Mail(from); err != nil {
+			return fmt.Errorf("Mail: %v", err)
+		}
 	}
 
 	for _, rec := range to {
@@ -242,7 +248,12 @@ func (s *sendmailSender) Send(from string, to []string, msg io.WriterTo) error {
 	var closeError error
 	var waitError error
 
-	args := []string{"-f", from, "-i"}
+	envelopeFrom := from
+	if setting.MailService.UseDifferentEnvelopeFrom {
+		envelopeFrom = setting.MailService.EnvelopeFrom
+	}
+
+	args := []string{"-f", envelopeFrom, "-i"}
 	args = append(args, setting.MailService.SendmailArgs...)
 	args = append(args, to...)
 	log.Trace("Sending with: %s %v", setting.MailService.SendmailPath, args)