Re: CNAME lookup failed temporarily. (#4.4.3) bounced emails

Keith,

In my email below, II failed to notice the Subject:

*CNAME lookup failed temporarily. (#4.4.3) bounced emails*
*
*
*You can (on your server from the command line) try:*
*
*
nslookup -type=mx comcast.com

Which will validate that you CAN do a cname lookup.

This error you are seeing, BTW means:

*The CNAME lookup failed temporarily. (#4.4.3) bounced emails*

Other things to check:

Make sure that /etc/resolv.conf is readable to 'others':
# ls -l /etc/resolv.conf
-rw-r--r-- 1 root root 0 2009-09-19 05:56 /etc/resolv.

Also check that nameservers set in /etc/resolv.conf can get MXes of
comcast.com and can resolve A records for those MXes.

# nslookup
>server=$sameserverasyour resolv.conf
>set type MX
>comcast.com
> quit or Control C

The error can also be caused by the fact that comcast.com has too many MX
records defined and response from DNS server exceeds limit of 512 bytes. If
this is the case then you can use one of qmail patches:
http://lifewithqmail.org/lwq.html#dns-patches

This error can also be indicative of an error with qmail when:

You are not using dnscache
You are using qmail without the BIG-DNS patch.

*TRY using smtproutes*:

An immediate workaround for qmail (if you cannot recompile it):

Use /var/qmail/control/smtproutes

Define one per line, a domain, and a server IP for deliveries to the
failing domain:
sympatico.ca:209.226.175.87

This link has some more detailed
information:http://wiki.qmailtoaster.com/index.php/Smtproutes


NOTE: That if your problem domain changes their MX, your entry will also
need to be updated.


On Wed, Nov 21, 2012 at 5:56 PM, Lisa Kachold <lisakachold@obnosis.com>wrote:

> Keith,
>
> On Wed, Nov 21, 2012 at 4:50 PM, keith smith <klsmith2020@yahoo.com>wrote:
>
>>
>> Hi,
>>
>>
>> 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
>>
>
> Does the IP address of this server match the sending domain?
> Do you have both a forward and reverse DNS record for that IP?
> Does the domain have a MX record?
>
> Since you are sending from a php scripted header, many of these automatic
> checks of mail to identify SPAM might not be automatically passed.
>
> One of the big ones that gets a server flagged is the dynamic nature of
> the mail server. I.E. it's reverse IP resolves as swipped to the hoster or
> the bandwidth provider as "dynamic".
>
> You are correct that a TXT DNS SPF (sender policy frameword) record might
> help here (as discussed in other email).
>
> Asking whoever provided your IP to also enter a reverse DNS entry alias
> that matches your server domain might assist.
>
> You can check your IPaddress "send score" here:
> https://www.senderscore.org/
>
> Of course as was already mentioned, be certain that you have not already
> been flagged for spam and your server is secure.
>
> Most of the big mail systems (including commercial types) use the same
> rules as spamassassin!
>
> The content of your email could contain some of the watchwords that push
> it over the edge to "reject":
>
> http://www.contactology.com/check_mqs.php
>
> The full email header and content from their server will assist you to see
> why it's being refused; send a command line sendmail debug to see why the
> server is denying it:
>
> /sbin/sendmail -d testemail@comcast.com
> sometext
> .
> .
> <wait for output>
>
> or pipe it to output:
>
> /sbin/sendmail -d testemail@comcast.com >/tmp/testemail
> sometext
> .
> .
> more /tmp/testemail
>
> You can test your mail's deliverability in various test tools:
> http://www.emailreach.com/
>
>
>
>
>
>> These emails are sent directly from the box, such as the order
>> confirmation email.
>>
>>
>> The problem started when we upgraded from CentOS 5.x to CentOS 6.x. I
>> wonder if anyone else has experience this problem.
>>
>>
>> The failure message:
>>
>> > Hi. This is the qmail-send program at [boxes fully qualified domain
>> name].
>> > I'm afraid I wasn't able to deliver your message to the following
>> addresses.
>> > This is a permanent error; I've given up. Sorry it didn't work out.
>> >
>> > [ <MEUSTACE2@COMCAST.NET>customers email address]:
>> > CNAME lookup failed temporarily. (#4.4.3) I'm not going to try again;
>> > this message has been in the queue too long.
>>
>> Only happens when emails are sent to Comcast directly from the server -
>> order confirmation and shipping confirmation.
>>
>> 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??
>>
>>
>> Is this true or could it be another issue?
>>
>>
>> Thank you for your feedback!
>>
>>
>> Keith
>>
>>
>>
>> ------------------------
>> Keith Smith
>>
>> --
>

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