[exim] SMTP error: subscribers are not permitted to directly…

Hello,
My ISP, comcast.net, does not allow direct connection to their mail
server. Below is a log entry of an attempt to send mail via SquirrlMail
-> Courier IMAP -> Exim.

Here is the bounced message:

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:

  zviman@???
    SMTP error from remote mail server after MAIL FROM:<muz@???> 
SIZE=1736:
    host gateway-r.comcast.net [204.127.198.26]: 550-69.250.247.7 blocked by
ldap:ou=rblmx,dc=comcast,dc=net
    550 Comcast.net subscribers are not permitted to directly connect to 
this mail
server. If you are a Comcast Commercial Services customer and need support,
please contact support_biz@???

------ This is a copy of the message, including all the headers. ------

Return-path: <muz@???>
Received: from localhost ([127.0.0.1] helo=www.zviman.name)
        by localhost.localdomain with esmtp (Exim 4.52)
        id 1FTrKb-0007AE-EE
        for zviman@???; Thu, 13 Apr 2006 02:13:13 +0000
Received: from 69.250.247.7
        (SquirrelMail authenticated user muz)
        by www.zviman.name with HTTP;
        Thu, 13 Apr 2006 02:13:13 -0000 (UTC)
Message-ID: <61215.69.250.247.7.1144894393.squirrel@www.zviman.name>
Date: Thu, 13 Apr 2006 02:13:13 -0000 (UTC)
Subject: test
From: muz@???
To: zviman@???
User-Agent: SquirrelMail/1.4.4
MIME-Version: 1.0
Content-Type: text/plain;charset=iso-8859-1
Content-Transfer-Encoding: 8bit
X-Priority: 3 (Normal)
Importance: Normal

test

Here is the Exim Log

2006-04-13 02:13:13 1FTrKb-0007AE-EE <= muz@??? H=localhost
(www.zviman.name) [127.0.0.1] P=esmtp S=691
id=61215.69.250.247.7.1144894393.squirrel@www.zviman.name
2006-04-13 02:13:14 1FTrKb-0007AE-EE ** zviman@??? R=dnslookup
T=remote_smtp: SMTP error from remote mail server after MAIL
FROM:<muz@???> SIZE=1736: host gateway-r.comcast.net
[204.127.198.26]: 550-69.250.247.7 blocked by
ldap:ou=rblmx,dc=comcast,dc=net\n550 Comcast.net subscribers are not
permitted to directly connect to this mail server. If you are a Comcast
Commercial Services customer and need support, please contact
support_biz@???
2006-04-13 02:13:14 1FTrKc-0007AN-3o <= <> R=1FTrKb-0007AE-EE
U=Debian-exim P=local S=1872
2006-04-13 02:13:14 1FTrKb-0007AE-EE Completed


I configured Thunderbird to use smtp.comcast.net as the smtp and we all
use my password. Is there a way to configure Exim to use the ISP server
or alternatively configure it to log to the sever as a user supplying a
password.


Thanks,


Muz