Incoming mail/DNS/MX issue

[jweinstein]

Hello,
We recently implemented a PePLink Balance 300 router which aggregates multiple WAN connections and also hosts our external DNS. The problem I am now encountering is that certain MX/DNS resolutions are not working properly for external users trying to send us email. I am still receiving email, even from large email providers like hotmail.com and gmail.com.

The domain in question is "ablonline.com".

For example, mail users at AOL.com are getting rejected when trying to send an email to me at "josh@ablonline.com", it gets rejected as the user "josh@

http://www.ablonline.com"

is not a valid email address. I have posted the email return error below. It appears that AOL is resolving our CNAME and although people are trying to send to @ablonline.com it is being resolved to @

http://www.ablonline.com

which our exchange server rejects.

If anyone has any insight as to what the issue might be with my DNS setup, please let me know.



AOL email error return:

The original message was received at Wed, 30 Apr 2008 12:01:47 -0400 (EDT)
from root@localhost


*** ATTENTION ***

Your e-mail is being returned to you because there was a problem with its
delivery. The address which was undeliverable is listed in the section
labeled: "----- The following addresses had permanent fatal errors -----".

The reason your mail is being returned to you is listed in the section
labeled: "----- Transcript of Session Follows -----".

The line beginning with "<<<" describes the specific reason your e-mail could
not be delivered. The next line contains a second error message which is a
general translation for other e-mail servers.

Please direct further questions regarding this message to the e-mail
administrator or Postmaster at that destination.

--AOL Postmaster



----- The following addresses had permanent fatal errors -----
<josh@ablonline.com>

----- Transcript of session follows -----
... while talking to

http://www.ablonline.com.:

>>> RCPT To:<josh@

http://www.ablonline.com>

<<< 550 5.7.1 Unable to relay for josh@

http://www.ablonline.com

550 <josh@ablonline.com>... User unknown

Final-Recipient: RFC822; josh@

http://www.ablonline.com

Action: failed
Status: 5.1.1
Remote-MTA: DNS;

http://www.ablonline.com

Diagnostic-Code: SMTP; 550 5.7.1 Unable to relay for josh@

http://www.ablonline.com

Last-Attempt-Date: Wed, 30 Apr 2008 12:07:19 -0400 (EDT)

Received: from Lanczglobal@aol.com
by imo-d23.mx.aol.com (mail_out_v38_r9.3.) id t.bf5.30200fcd (37564)
for <josh@ablonline.com>; Wed, 30 Apr 2008 12:01:47 -0400 (EDT)
Return-Path: <lanczglobal@aol.com>
Received: from FWM-D19 (fwm-d19.webmail.aol.com [205.188.160.211]) by
cia-mb04.mx.aol.com (v121.5) with ESMTP id MAILCIAMB041-92bc481897eb10d; Wed, 30
Apr 2008 12:01:47 -0400
To: josh@ablonline.com
Date: Wed, 30 Apr 2008 12:01:47 -0400
X-MB-Message-Source: WebUI
X-AOL-IP: 72.240.120.108
X-MB-Message-Type: User
MIME-Version: 1.0
From: lanczglobal@aol.com
Content-Type: multipart/alternative;
boundary="--------MB_8CA78F2A0A476F4_1B1C_FF8_FWM-D19.sysops.aol.com"
X-Mailer: AOL Webmail 36240-STANDARD
Received: from 72.240.120.108 by FWM-D19.sysops.aol.com (205.188.160.211) with
HTTP (WebMailUI); Wed, 30 Apr 2008 12:01:46 -0400
Message-Id: <8CA78F2A042B661-1B1C-810@FWM-D19.sysops.aol.com>
X-Spam-Flag: NO

 

[elgrandeperro]

Did you change it already? I see the MX records correct:

> ablonline.com
Server: 140.172.10.9
Address: 140.172.10.9#53

Non-authoritative answer:
ablonline.com mail exchanger = 5 mail.ablonline.com.
ablonline.com mail exchanger = 10 mail1.ablonline.com.

Authoritative answers can be found from:
ablonline.com nameserver = ns1.ablonline.com.
ablonline.com nameserver = ns2.ablonline.com.
mail.ablonline.com internet address = 99.158.189.242
mail1.ablonline.com internet address = 72.240.120.108
>

I'll assume you might have had a CNAME like:

@ IN CNAME

http://www.ablonline.com.

or
* IN CNAME

http://www.ablonline.com.

 

[jweinstein]

No, I haven't changed anything as of yet. I do have a CNAME record for host "ablonline.com" (or blank host) pointing to reference "

http://www".

I have attached a screenshot of the PePLink DNS configuration.

 

[elgrandeperro]

Oh, that might be the problem.
Use a A record for ablonline.com (to the IP of www) instead and take out the CNAME. I don't see it on the screen shot, but setting a A record for the domain is a common thing.

And of course leave the MX records for ablonline.com.

 

[jweinstein]

I removed that CNAME for

http://www.ablonline.com.

Currently I have an A record for "www" resolving to the two IPs. Do I need a blank A record (for ablonline.com) also to the same two IPs?

Thanks,
Josh

 

[elgrandeperro]

The only reason for the A is to allow browsers to go the web site without the www. So yes, if you want that.

I hope your tool will allow it. In bind, it would be @ (for the current domain)

 

[jweinstein]

I believe it does allow for it, I have since made the change already. See if you can browse to each and let me know:

http://www.ablonline.com

http://ablonline.com

 

[elgrandeperro]

I get the right results, both from nslookup and browser.

 

[jweinstein]

Great, thanks so much for the help!

 

[elgrandeperro]

BTW, I believe the AOL mailer to be faulty. It should only query for MX records, not As or CNAMEs. It should not change the recipient because of the CNAME. The notion that an email domain is on a single host is arcane.