diff --git a/docsrc/imap/reference/manpages/systemcommands/smmapd.rst b/docsrc/imap/reference/manpages/systemcommands/smmapd.rst
index 428dca8e75..20b432b194 100644
--- a/docsrc/imap/reference/manpages/systemcommands/smmapd.rst
+++ b/docsrc/imap/reference/manpages/systemcommands/smmapd.rst
@@ -8,28 +8,38 @@
 **smmapd**
 ==========
 
-Sendmail socket map daemon
+Sendmail and Postfix socket map daemon
 
 Synopsis
 ========
 
 .. parsed-literal::
 
-    **smmapd** [ **-C** *config-file* ]  [ **-U** *uses* ] [ **-T** *timeout* ] [ **-D** ]
+    **smmapd** [ **-C** *config-file* ]  [ **-U** *uses* ] [ **-T** *timeout* ] [ **-D** ] [**-p**]
 
 Description
 ===========
 
-**smmapd** is a Sendmail socket map daemon which is used to verify that
-a Cyrus mailbox exists, that it is postable and it is under quota.  It
+**smmapd** is a Sendmail and Postfix socket map daemon which is used to verify
+that a Cyrus mailbox exists, that it is postable, it is not blocked for the
+smmapd service in the userdeny database, and it is under quota.  It
 accepts commands on its standard input and responds on its standard
 output.  It MUST be invoked by :cyrusman:`master(8)` with those
-descriptors attached to a remote client connection.  The service ignores
-the userdeny database.  The received queries contain map name followed by
-mailbox, **smmapd** ignores the map name.  Queries with plus addressing return
-*OK* if the user has a mailbox with the name after plus, otherwise the result
-is *NOTFOUND*.  Match for the mailbox after plus is performed case-sensitive,
-for the address before the plus - case-insensitive.
+descriptors attached to a remote client connection.  The received queries
+contain map name followed by mailbox, **smmapd** ignores the map name.
+Queries with plus addressing, when *-p* is not passed, return *OK* when
+the user has a mailbox with the name after plus, otherwise the result
+is *NOTFOUND*.  Match for the mailbox after plus is performed
+case-sensitive, for the address before the plus - depends on
+`lmtp_downcase_rcpt`.
+
+The use case is to verify in Sendmail or Postfix if the destination exists,
+before accepting an email.  Then, if `autocreate_sieve_folders` is set, but
+the folder does not exist yet, **smmapd** will return *NOTFOUND*, unless *-p*
+is passed.  Another use case is to do something in a Sieve script with emails,
+based on plus addressing, without delivering them in the correspondent sub-folder.
+To accept such emails, when the folder with the same name does not exist, *-p* must
+be passed.
 
 **smmapd** |default-conf-text|
 
@@ -57,6 +67,11 @@ Options
 
     Run external debugger specified in debug_command.
 
+.. option:: -p
+
+    Skip plus addressing: everything from `+` until `@`.  When looking up the userdeny
+    database, plus addressing is always skipped, irrespective of this option.
+
 Examples
 ========
 
diff --git a/imap/smmapd.c b/imap/smmapd.c
index 1be389d74f..e6d4e6468f 100644
--- a/imap/smmapd.c
+++ b/imap/smmapd.c
@@ -75,7 +75,6 @@
  */
 
 #include <config.h>
-
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
 #endif
@@ -93,6 +92,7 @@
 #include "proc.h"
 #include "quota.h"
 #include "slowio.h"
+#include "userdeny.h"
 #include "util.h"
 #include "xmalloc.h"
 #include "xstrlcpy.h"
@@ -104,7 +104,9 @@
 const char *BB;
 static int forcedowncase;
 
-extern int optind;
+extern int optind, opterr;
+extern char *optarg;
+static int skipplus;
 
 static struct protstream *map_in, *map_out;
 static const char *smmapd_clienthost;
@@ -175,7 +177,7 @@ EXPORTED void fatal(const char* s, int code)
  */
 int service_init(int argc, char **argv, char **envp)
 {
-    int r;
+    int r, opt;
 
     if (geteuid() == 0) fatal("must run as the Cyrus user", EX_USAGE);
     proc_settitle_init(argc, argv, envp);
@@ -192,6 +194,17 @@ int service_init(int argc, char **argv, char **envp)
         fatal(error_message(r), EX_CONFIG);
     }
 
+    while ((opt = getopt(argc, argv, "p")) != EOF) {
+        switch(opt) {
+        case 'p':
+            skipplus = 1;
+            break;
+        default:
+            syslog(LOG_ERR, "usage: smmapd [-C <alt_config>] [-U uses] [-T timeout] [-D] [-p]");
+            exit(EX_USAGE);
+        }
+    }
+
     return 0;
 }
 
@@ -242,14 +255,21 @@ static int verify_user(const char *key, struct auth_state *authstate)
 
     mbname_t *mbname = mbname_from_recipient(key, &map_namespace);
 
+    if (skipplus) mbname_set_boxes(mbname, NULL);
     if (forcedowncase) mbname_downcaseuser(mbname);
 
-    /* see if its a shared mailbox address */
+    /* see if it is a shared mailbox address */
     if (!strcmpsafe(mbname_userid(mbname), BB)) {
         mbname_set_localpart(mbname, NULL);
         mbname_set_domain(mbname, NULL);
     }
 
+    char msg[MAX_MAILBOX_PATH+1];
+    if (userdeny(mbname_userid(mbname), config_ident, msg, sizeof(msg))) {
+        prot_printf(map_out, SIZE_T_FMT ":NOTFOUND %s,", 9 + strlen(msg), msg);
+        mbname_free(&mbname);
+        return -1;
+    }
     /*
      * check to see if mailbox exists and we can append to it:
      *