diff --git a/include/curl/curl.h b/include/curl/curl.h
index 3c9c41d8a..f2501cd2b 100644
--- a/include/curl/curl.h
+++ b/include/curl/curl.h
@@ -1518,6 +1518,9 @@ typedef enum {
   /* Enable/disable specific SSL features with a bitmask, see CURLSSLOPT_* */
   CINIT(SSL_OPTIONS, LONG, 216),
 
+  /* set the SMTP auth originator */
+  CINIT(MAIL_AUTH, OBJECTPOINT, 217),
+
   CURLOPT_LASTENTRY /* the last unused */
 } CURLoption;
 
diff --git a/lib/smtp.c b/lib/smtp.c
index 95e71d75a..c02c9bdd4 100644
--- a/lib/smtp.c
+++ b/lib/smtp.c
@@ -893,6 +893,7 @@ static CURLcode smtp_state_auth_resp(struct connectdata *conn,
 static CURLcode smtp_mail(struct connectdata *conn)
 {
   char *from = NULL;
+  char *auth = NULL;
   char *size = NULL;
   CURLcode result = CURLE_OK;
   struct SessionHandle *data = conn->data;
@@ -909,26 +910,49 @@ static CURLcode smtp_mail(struct connectdata *conn)
   if(!from)
     return CURLE_OUT_OF_MEMORY;
 
-  /* calculate the optional SIZE parameter */
-  if(conn->data->set.infilesize > 0) {
-    size = aprintf("%" FORMAT_OFF_T, data->set.infilesize);
+  /* calculate the optional AUTH parameter */
+  if(data->set.str[STRING_MAIL_AUTH] && conn->proto.smtpc.authused) {
+    if(data->set.str[STRING_MAIL_AUTH][0] == '<')
+      auth = aprintf("%s", data->set.str[STRING_MAIL_AUTH]);
+    else
+      auth = aprintf("<%s>", data->set.str[STRING_MAIL_AUTH]);
 
-    if(!size) {
+    if(!auth) {
       Curl_safefree(from);
 
       return CURLE_OUT_OF_MEMORY;
     }
   }
 
-  /* send MAIL FROM */
-  if(!size)
-    result = Curl_pp_sendf(&conn->proto.smtpc.pp, "MAIL FROM:%s", from);
-  else
-    result = Curl_pp_sendf(&conn->proto.smtpc.pp, "MAIL FROM:%s SIZE=%s",
-                           from, size);
+  /* calculate the optional SIZE parameter */
+  if(conn->data->set.infilesize > 0) {
+    size = aprintf("%" FORMAT_OFF_T, data->set.infilesize);
+
+    if(!size) {
+      Curl_safefree(from);
+      Curl_safefree(auth);
+
+      return CURLE_OUT_OF_MEMORY;
+    }
+  }
+
+  /* send MAIL FROM */
+  if(!auth && !size)
+    result = Curl_pp_sendf(&conn->proto.smtpc.pp,
+                           "MAIL FROM:%s", from);
+  else if(auth && !size)
+    result = Curl_pp_sendf(&conn->proto.smtpc.pp,
+                           "MAIL FROM:%s AUTH=%s", from, auth);
+  else if(auth && size)
+    result = Curl_pp_sendf(&conn->proto.smtpc.pp,
+                           "MAIL FROM:%s AUTH=%s SIZE=%s", from, auth, size);
+  else
+    result = Curl_pp_sendf(&conn->proto.smtpc.pp,
+                           "MAIL FROM:%s SIZE=%s", from, size);
 
-  Curl_safefree(size);
   Curl_safefree(from);
+  Curl_safefree(auth);
+  Curl_safefree(size);
 
   if(result)
     return result;
@@ -1308,7 +1332,7 @@ static CURLcode smtp_connect(struct connectdata *conn,
   pp->conn = conn;
 
   if(!*path) {
-    if(!Curl_gethostname(localhost, sizeof localhost))
+    if(!Curl_gethostname(localhost, sizeof(localhost)))
       path = localhost;
     else
       path = "localhost";
diff --git a/lib/url.c b/lib/url.c
index 277078ebf..c4e84550f 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -2402,6 +2402,11 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option,
                        va_arg(param, char *));
     break;
 
+  case CURLOPT_MAIL_AUTH:
+    result = setstropt(&data->set.str[STRING_MAIL_AUTH],
+                       va_arg(param, char *));
+    break;
+
   case CURLOPT_MAIL_RCPT:
     /* get a list of mail recipients */
     data->set.mail_rcpt = va_arg(param, struct curl_slist *);
diff --git a/lib/urldata.h b/lib/urldata.h
index 0463006c6..1f3853dc7 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -1335,6 +1335,7 @@ enum dupstring {
   STRING_SOCKS5_GSSAPI_SERVICE,  /* GSSAPI service name */
 #endif
   STRING_MAIL_FROM,
+  STRING_MAIL_AUTH,
 
 #ifdef USE_TLS_SRP
   STRING_TLSAUTH_USERNAME,     /* TLS auth <username> */