<font color="#3333ff" face="tahoma, sans-serif">Check that your server is not on any RBL list (real time black hole list).</font><div><font color="#3333ff" face="tahoma, sans-serif">Alternately set up a smart host to send through a provider they don't block (like gmail/google apps for domains).<br>
</font>You can test manually using telnet.</div><div>First get their mail exchange records:</div><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><blockquote style="margin:0 0 0 40px;border:none;padding:0px">
<div><div><font color="#222222" face="arial, sans-serif">nslookup -query=MX <a href="http://comcast.com">comcast.com</a></font></div></div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div>
<font color="#222222" face="arial, sans-serif">Server: x.x.x.x</font></div></div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif">Address:<span class="Apple-tab-span" style="white-space:pre"> </span>y.y.y.y#53</font></div>
</div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><br></font></div></div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px">
<div><div><font color="#222222" face="arial, sans-serif">Non-authoritative answer:</font></div></div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><a href="http://comcast.com">comcast.com</a><span class="Apple-tab-span" style="white-space:pre"> </span>mail exchanger = 5 <a href="http://mx1.comcast.com">mx1.comcast.com</a>.</font></div>
</div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><a href="http://comcast.com">comcast.com</a><span class="Apple-tab-span" style="white-space:pre"> </span>mail exchanger = 5 <a href="http://mx2.comcast.com">mx2.comcast.com</a>.</font></div>
</div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><a href="http://comcast.com">comcast.com</a><span class="Apple-tab-span" style="white-space:pre"> </span>mail exchanger = 5 <a href="http://mx3.comcast.com">mx3.comcast.com</a>.</font></div>
</div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><a href="http://comcast.com">comcast.com</a><span class="Apple-tab-span" style="white-space:pre"> </span>mail exchanger = 5 <a href="http://mx4.comcast.com">mx4.comcast.com</a>.</font></div>
</div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><br></font></div></div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px">
<div><div><font color="#222222" face="arial, sans-serif">Authoritative answers can be found from:</font></div></div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><a href="http://comcast.com">comcast.com</a><span class="Apple-tab-span" style="white-space:pre"> </span>nameserver = <a href="http://dns101.comcast.net">dns101.comcast.net</a>.</font></div>
</div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><a href="http://comcast.com">comcast.com</a><span class="Apple-tab-span" style="white-space:pre"> </span>nameserver = <a href="http://dns102.comcast.net">dns102.comcast.net</a>.</font></div>
</div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><a href="http://comcast.com">comcast.com</a><span class="Apple-tab-span" style="white-space:pre"> </span>nameserver = <a href="http://dns103.comcast.net">dns103.comcast.net</a>.</font></div>
</div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><a href="http://comcast.com">comcast.com</a><span class="Apple-tab-span" style="white-space:pre"> </span>nameserver = <a href="http://dns104.comcast.net">dns104.comcast.net</a>.</font></div>
</div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><a href="http://comcast.com">comcast.com</a><span class="Apple-tab-span" style="white-space:pre"> </span>nameserver = <a href="http://dns105.comcast.net">dns105.comcast.net</a>.</font></div>
</div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><a href="http://mx1.comcast.com">mx1.comcast.com</a><span class="Apple-tab-span" style="white-space:pre"> </span>internet address = 76.96.32.247</font></div>
</div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><a href="http://mx2.comcast.com">mx2.comcast.com</a><span class="Apple-tab-span" style="white-space:pre"> </span>internet address = 76.96.32.252</font></div>
</div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><a href="http://mx3.comcast.com">mx3.comcast.com</a><span class="Apple-tab-span" style="white-space:pre"> </span>internet address = 69.241.43.117</font></div>
</div></blockquote><blockquote style="margin:0 0 0 40px;border:none;padding:0px"><div><div><font color="#222222" face="arial, sans-serif"><a href="http://mx4.comcast.com">mx4.comcast.com</a><span class="Apple-tab-span" style="white-space:pre"> </span>internet address = 69.241.43.118</font></div>
</div></blockquote></blockquote><div><br></div><div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">telnet </span><span style="color:rgb(34,34,34);font-family:arial,sans-serif">76.96.32.24 </span><span style="background-color:rgb(255,255,255);color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">25</span></div>
<div><span class="il" style="background-color:rgb(255,255,204);color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">helo</span><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)"> <your server name></span><br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">mail </span><a href="mailto:from%3Aroot@san.mesacc.edu" target="_blank" style="color:rgb(17,85,204);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">from:<</a>user>@<your server name><br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">rcpt </span><a href="mailto:to%3Asean.parsons@mesacc.edu" target="_blank" style="color:rgb(17,85,204);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">to:<user2>@c</a><a href="http://omcast.com">omcast.com</a><br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">This is a test email</span><br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">.</span><br style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px;background-color:rgb(255,255,255)">
<br><br><div class="gmail_quote">On Wed, Nov 21, 2012 at 4:50 PM, keith smith <span dir="ltr"><<a href="mailto:klsmith2020@yahoo.com" target="_blank">klsmith2020@yahoo.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<table cellspacing="0" cellpadding="0" border="0"><tbody><tr><td valign="top" style="font:inherit"><br>
<p style="margin-bottom:0in">Hi,</p>
<p style="margin-bottom:0in"><br>
</p>
<p style="margin-bottom:0in">One of the Vhost on a server I run is a
shopping cart. We have been experiencing bounced emails when sending to Comcast. We do not have this problem with any other ISP.</p>
<p style="margin-bottom:0in"><br>
</p>
<p style="margin-bottom:0in">These emails are sent directly from the
box, such as the order confirmation email.</p>
<p style="margin-bottom:0in"><br>
</p>
<p style="margin-bottom:0in">The problem started when we upgraded
from CentOS 5.x to CentOS 6.x. I wonder if anyone else has
experience this problem.</p>
<p style="margin-bottom:0in"><br>
</p>
<p style="margin-bottom:0in">The failure message: <br><br>> Hi.
This is the qmail-send program at [boxes fully qualified domain
name]. <br>> I'm afraid I wasn't able to deliver your message to
the following <br>addresses. <br>> This is a permanent error; I've
given up. Sorry it didn't work out. <br>> <br>> <a href="mailto:MEUSTACE2@COMCAST.NET" target="_blank">[</a>customers
email address]: <br>> CNAME lookup failed temporarily. (#4.4.3)
I'm not going to try again; <br>> this message has been in the
queue too long. <br><br>Only happens when emails are sent to Comcast
directly from the server - order confirmation and shipping
confirmation. <br><br>I've search for a solution and read this can be
corrected by setting the DISABLE_CNAME_LOOKUP in qmail-remote. Something about a buffer being too small??<br></p>
<p style="margin-bottom:0in"><br>
</p>
<p style="margin-bottom:0in">Is this true or could it be another
issue?
</p>
<p style="margin-bottom:0in"><br>
</p>
<p style="margin-bottom:0in">Thank you for your feedback!</p>
<p style="margin-bottom:0in"><br>Keith
</p>
<br><br><br>------------------------<br>
Keith Smith</td></tr></tbody></table><br>---------------------------------------------------<br>
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