Thanks to WHMCS support, finally found the correct e-mail to ban, and the deluge is stopped. I would like to find out, though, what I did to cause this because I'm afraid of doing it again! It happened when I replied to a client's support ticket.
I'll need to un-ban mailer-daemon which was sending the e-mails at some point, so I want to get to the bottom of this. I don't really know how to understand e-mail headers, but if anyone else does, here's what they say (I am Burke DesignHost):
This message was created automatically by mail delivery software.
A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:
root@lagonda.websitewelcome.com
(ultimately generated from Mailer-Daemon@lagonda.websitewelcome.com)
retry timeout exceeded
------ This is a copy of the message, including all the headers. ------
Return-path: <support@burkedesignhost.com>
Received: from [174.120.168.218] (port=43526 helo=localhost.localdomain)
by lagonda.websitewelcome.com with esmtpa (Exim 4.69)
(envelope-from <support@burkedesignhost.com>)
id 1NV7rt-0007Cn-13
for Mailer-Daemon@lagonda.websitewelcome.com; Wed, 13 Jan 2010 12:22:57 -0600
Date: Wed, 13 Jan 2010 12:22:56 -0600
To: Mailer-Daemon@lagonda.websitewelcome.com
From: Burke DesignHost <support@burkedesignhost.com>
Subject: Support Ticket Not Opened
Message-ID: <849bf2101f6716094faa024f11868c52@localhost.localdomain>
X-Priority: 3
MIME-Version: 1.0
Content-Type: multipart/alternative;
boundary="b1_849bf2101f6716094faa024f11868c52"
--b1_849bf2101f6716094faa024f11868c52
Content-Type: text/plain; charset = "utf-8"
Content-Transfer-Encoding: 8bit
Mail Delivery System ,
Your email to our support system could not be accepted because it was not recognized as coming from an e-mail address belonging to one of our customers. If you need assistance, please e-mail from the address you used to register with us and that you use to log in to our client area.
Burke DesignHost
http://www.burkedesignhost.com
--b1_849bf2101f6716094faa024f11868c52
Content-Type: text/html; charset = "utf-8"
Content-Transfer-Encoding: 8bit
<font style="font-family:Verdana;font-size:11px"><p>Mail Delivery System ,</p>
<p>Your email to our support system could not be accepted because it was not recognized as coming from an e-mail address belonging to one of our customers. If you need assistance, please e-mail from the address you used to register with us and that you use to log in to our client area.</p>
<p>Burke DesignHost<br />
www.burkedesignhost.com</p>
--b1_849bf2101f6716094faa024f11868c52--
Does anyone have any ideas?