diff --git a/mailnews/base/public/nsIMsgIncomingServer.idl b/mailnews/base/public/nsIMsgIncomingServer.idl
index 3114e3a215cf..dadfc27e1b55 100644
--- a/mailnews/base/public/nsIMsgIncomingServer.idl
+++ b/mailnews/base/public/nsIMsgIncomingServer.idl
@@ -56,7 +56,7 @@ interface nsIUrlListener;
  * often you will want to add extra interfaces that give you server-specific
  * attributes and methods.
  */
-[scriptable, uuid(55569286-ee09-45ec-a83b-96d0273a5ed8)]
+[scriptable, uuid(dc2f06f9-0ee8-47ad-901e-168d14323576)]
 interface nsIMsgIncomingServer : nsISupports {
 
   /**
@@ -178,6 +178,11 @@ interface nsIMsgIncomingServer : nsISupports {
   /* should we use secure authentication? */
   attribute boolean useSecAuth;
 
+  /* if a logon mechanism fails, should we fallback to a different
+     mechanism?
+  */
+  attribute boolean logonFallback;
+
   /* can server support a secure channel? */
   readonly attribute boolean isSecureServer;
 
diff --git a/mailnews/base/util/nsMsgIncomingServer.cpp b/mailnews/base/util/nsMsgIncomingServer.cpp
index a8a76b9baafe..e2fcf88ab6f2 100644
--- a/mailnews/base/util/nsMsgIncomingServer.cpp
+++ b/mailnews/base/util/nsMsgIncomingServer.cpp
@@ -1727,6 +1727,7 @@ NS_IMPL_SERVERPREF_STR(nsMsgIncomingServer, Username, "userName")
 NS_IMPL_SERVERPREF_STR(nsMsgIncomingServer, PrefPassword, "password")
 NS_IMPL_SERVERPREF_BOOL(nsMsgIncomingServer, IsSecure, "isSecure")
 NS_IMPL_SERVERPREF_BOOL(nsMsgIncomingServer, UseSecAuth, "useSecAuth")
+NS_IMPL_SERVERPREF_BOOL(nsMsgIncomingServer, LogonFallback, "logon_fallback");
 NS_IMPL_SERVERPREF_INT(nsMsgIncomingServer, BiffMinutes, "check_time")
 NS_IMPL_SERVERPREF_STR(nsMsgIncomingServer, Type, "type")
 // in 4.x, this was "mail.pop3_gets_new_mail" for pop and 
diff --git a/mailnews/local/src/nsMovemailIncomingServer.cpp b/mailnews/local/src/nsMovemailIncomingServer.cpp
index 3b9f699a08e1..3d24d1c9b91f 100644
--- a/mailnews/local/src/nsMovemailIncomingServer.cpp
+++ b/mailnews/local/src/nsMovemailIncomingServer.cpp
@@ -76,7 +76,7 @@ nsresult
 nsMovemailIncomingServer::GetLocalStoreType(char **type)
 {
     NS_ENSURE_ARG_POINTER(type);
-    *type = nsCRT::strdup("mailbox");
+    *type = strdup("mailbox");
     return NS_OK;
 }
 
diff --git a/mailnews/local/src/nsPop3Protocol.cpp b/mailnews/local/src/nsPop3Protocol.cpp
index 4db6e50df22b..da3c9b5c8d3b 100644
--- a/mailnews/local/src/nsPop3Protocol.cpp
+++ b/mailnews/local/src/nsPop3Protocol.cpp
@@ -705,10 +705,12 @@ nsresult nsPop3Protocol::GetPassword(char ** aPassword, PRBool *okayValue)
     nsXPIDLString passwordTemplate;
     // if the last prompt got us a bad password then show a special dialog
     if (TestFlag(POP3_PASSWORD_FAILED))
-    { 
-      // if we haven't successfully logged onto the server in this session,
+    {
+      // if we haven't successfully logged onto the server in this session
+      // and tried at least twice or if the server threw the specific error,
       // forget the password.
-      if (!isAuthenticated && m_pop3ConData->logonFailureCount > 1)
+      if ((!isAuthenticated && m_pop3ConData->logonFailureCount > 1) ||
+          TestFlag(POP3_AUTH_FAILURE))
         rv = server->ForgetPassword();
       if (NS_FAILED(rv)) return rv;
       mStringService->GetStringByID(POP3_PREVIOUSLY_ENTERED_PASSWORD_IS_INVALID_ETC, getter_Copies(passwordTemplate));
@@ -733,7 +735,7 @@ nsresult nsPop3Protocol::GetPassword(char ** aPassword, PRBool *okayValue)
       nsTextFormatter::smprintf_free(passwordPromptString);
     }
     
-    ClearFlag(POP3_PASSWORD_FAILED);
+    ClearFlag(POP3_PASSWORD_FAILED|POP3_AUTH_FAILURE);
     if (NS_FAILED(rv))
       m_pop3ConData->next_state = POP3_ERROR_DONE;
   } // if we have a server
@@ -982,13 +984,14 @@ nsPop3Protocol::WaitForResponse(nsIInputStream* inputStream, PRUint32 length)
   
   if(pauseForMoreData || !line)
   {
-    m_pop3ConData->pause_for_read = PR_TRUE; /* don't pause */
+    m_pop3ConData->pause_for_read = PR_TRUE; /* pause */
+
     PR_Free(line);
     return(ln);
   }
-  
+
   PR_LOG(POP3LOGMODULE, PR_LOG_ALWAYS,("RECV: %s", line));
-  
+
   if(*line == '+')
   {
     m_pop3ConData->command_succeeded = PR_TRUE;
@@ -1383,7 +1386,15 @@ PRInt32 nsPop3Protocol::AuthFallback()
                          ? POP3_PASSWORD_FAILURE : POP3_USERNAME_FAILURE));
 
         // response code received shows that server is certain about the
-        // credential was wrong -> no fallback, show alert and pw dialog
+        // credential was wrong, or fallback has been disabled by pref
+        // -> no fallback, show alert and pw dialog
+        PRBool logonFallback = PR_TRUE;
+        nsCOMPtr<nsIMsgIncomingServer> server = do_QueryInterface(m_pop3Server);
+        if (server)
+          server->GetLogonFallback(&logonFallback);
+        if (!logonFallback)
+          SetFlag(POP3_AUTH_FAILURE);
+
         if (TestFlag(POP3_AUTH_FAILURE))
         {
             Error((m_password_already_sent) 
diff --git a/mailnews/mailnews.js b/mailnews/mailnews.js
index dacea380a1ad..b15b0c596e55 100644
--- a/mailnews/mailnews.js
+++ b/mailnews/mailnews.js
@@ -389,6 +389,7 @@ pref("mail.server.default.login_at_startup", false);
 pref("mail.server.default.allows_specialfolders_usage", true);
 pref("mail.server.default.canCreateFolders", true);
 pref("mail.server.default.canFileMessages", true);
+pref("mail.server.default.logon_fallback", true);
 
 // special enhancements for IMAP servers
 pref("mail.server.default.store_read_mail_in_pfc", false);