Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261512AbTIXQpt (ORCPT ); Wed, 24 Sep 2003 12:45:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261514AbTIXQps (ORCPT ); Wed, 24 Sep 2003 12:45:48 -0400 Received: from 81-2-122-30.bradfords.org.uk ([81.2.122.30]:29568 "EHLO 81-2-122-30.bradfords.org.uk") by vger.kernel.org with ESMTP id S261512AbTIXQps (ORCPT ); Wed, 24 Sep 2003 12:45:48 -0400 Date: Wed, 24 Sep 2003 17:45:28 +0100 From: John Bradford Message-Id: <200309241645.h8OGjS9i000412@81-2-122-30.bradfords.org.uk> To: david.lang@digitalinsight.com, john@grabjohn.com Subject: Re: Horiffic SPAM Cc: andrea@suse.de, linux-kernel@vger.kernel.org, rjohnson@analogic.com Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 778 Lines: 20 > if you want to block mail you need to have your MTA return a 500 series > error code when it gets a connection from that IP address, otherwise the > sending MTA will just retry later, resulting in the problem described. Read my post again. A lot of the simple SMTP engines embedded in viruses _don't_ retry on 4xx error codes. Real SMTP engines do. That flaw is what we are taking advantage of, to filter out the junk. I.E. we tell everybody 'come back later'. Genuine mail does, whilst junk mail often doesn't bother. John. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/