--- spamass-milter.1.in
+++ spamass-milter.1.in
@@ -16,6 +16,7 @@
 .Op Fl f
 .Op Fl g Ar group
 .Op Fl i Ar networks
+.Op Fl I
 .Op Fl m
 .Op Fl M
 .Op Fl P Ar pidfile
@@ -134,6 +135,8 @@ Multiple
 flags will append to the list.
 For example, if you list all your internal networks, no outgoing emails
 will be filtered.
+.It Fl I
+Ignores messages if the sender has authenticated via SMTP AUTH.
 .It Fl m
 Disables modification of the 
 .Ql Subject: 
--- spamass-milter.cpp
+++ spamass-milter.cpp
@@ -178,6 +178,7 @@ bool flag_full_email = false;		/* pass f
 bool flag_expand = false;	/* alias/virtusertable expansion */
 bool warnedmacro = false;	/* have we logged that we couldn't fetch a macro? */
 bool auth = false;		/* don't scan authenticated users */
+bool ignore_authenticated_senders = false;     /* authenticated users bypass spam checks */
 
 // {{{ main()
 
@@ -185,7 +186,7 @@ int
 main(int argc, char* argv[])
 {
    int c, err = 0;
-   const char *args = "afd:mMp:P:r:u:D:i:b:B:e:xS:R:C:g:";
+   const char *args = "afd:mMp:P:r:u:D:i:Ib:B:e:xS:R:C:g:";
    char *sock = NULL;
    char *group = NULL;
    bool dofork = false;
@@ -225,6 +226,10 @@ main(int argc, char* argv[])
                 debug(D_MISC, "Parsing ignore list");
                 parse_networklist(optarg, &ignorenets);
                 break;
+            case 'I':
+                debug(D_MISC, "Ignore authenticated senders");
+                ignore_authenticated_senders = true;
+                break;
             case 'm':
                 dontmodifyspam = true;
                 smfilter.xxfi_flags &= ~SMFIF_CHGBODY;
@@ -301,7 +306,7 @@ main(int argc, char* argv[])
       cout << PACKAGE_NAME << " - Version " << PACKAGE_VERSION << endl;
       cout << "SpamAssassin Sendmail Milter Plugin" << endl;
       cout << "Usage: spamass-milter -p socket [-b|-B bucket] [-d xx[,yy...]] [-D host]" << endl;
-      cout << "                      [-e defaultdomain] [-f] [-i networks] [-m] [-M]" << endl;
+      cout << "                      [-e defaultdomain] [-f] [-i networks] [-I] [-m] [-M]" << endl;
       cout << "                      [-P pidfile] [-r nn] [-u defaultuser] [-x] [-a]" << endl;
       cout << "                      [-C rejectcode] [-R rejectmsg] [-g group]" << endl;
       cout << "                      [-- spamc args ]" << endl;
@@ -318,6 +323,7 @@ main(int argc, char* argv[])
       cout << "   -g group: socket group (perms to 660 as well)" << endl;
       cout << "   -i: skip (ignore) checks from these IPs or netblocks" << endl;
       cout << "          example: -i 192.168.12.5,10.0.0.0/8,172.16.0.0/255.255.0.0" << endl;
+      cout << "   -I: skip (ignore) checks if sender is authenticated" << endl;
       cout << "   -m: don't modify body, Content-type: or Subject:" << endl;
       cout << "   -M: don't modify the message at all" << endl;
       cout << "   -P pidfile: Put processid in pidfile" << endl;
@@ -850,6 +856,22 @@ mlfi_envfrom(SMFICTX* ctx, char** envfro
       return SMFIS_ACCEPT;
     }
   }
+
+  if (ignore_authenticated_senders)
+  {
+    char *auth_authen;
+
+    auth_authen = smfi_getsymval(ctx, const_cast<char *>("{auth_authen}"));
+    debug(D_MISC, "auth_authen=%s", auth_authen ?: "<unauthenticated>");
+
+    if (auth_authen)
+    {
+      debug(D_MISC, "sender authenticated (%s) - accepting message",
+	    auth_authen);
+      debug(D_FUNC, "mlfi_envfrom: exit ignore");
+      return SMFIS_ACCEPT;
+    }
+  }
 
   debug(D_FUNC, "mlfi_envfrom: enter");
   try {