Warning - Reverse DNS does not match SMTP Banner

wendy@mxtoolbox.com · **Posted:** Mon Nov 21, 2011 9:43 am

Johan,

Yes, this post is still active. What issues are you having?

Thanks,
Wendy

gmoneyreg · **Joined:** Fri Nov 25, 2011 6:26 pm **Posts:** 0

Greetings Wendy,

I am experiencing the same issue as shin234:

shin234 wrote:
> i have the same issue but our smtp header matches the ptr record perfectly. and it
> is not being masked. but i still get the Warning - Reverse DNS does not match SMTP
> Banner error and my emails are still stuck in the queue

My records all seem to be in line, however I am receiving the "Warning" and emails are not being delivered to some domains. I am uncertain at this point where the issue may lie.

Any help would be greatly appreciated.

Thank you in advance.

wendy@mxtoolbox.com · **Posted:** Wed Nov 30, 2011 8:36 am

Sorry to hear you are having issues, if you could provide your domain or IP I can some additional testing.

Thanks,
Wendy

Oclaner_IT · **Posted:** Sat Mar 03, 2012 5:01 pm

Hi

I wasn't able to add FQDN in the Org. Configuration->Hun Transport. It is because I don't have the admin right? Or is the ISP problem?

Northbrook_IT · **Joined:** Mon Feb 06, 2012 10:13 am **Posts:** 0

I have what may be a less than usual situation, wondering if anyone using MXToolBox has run into this problem. I'm also getting Reverse DNS errors. My company has 3 data connections from 3 separate providers that all connect to one mail server. I have an MX record for each line, and they all are passing inbound/outbound email without a problem.

The Rev DNS error only shows up for the 2 new lines, our original one does not have any errors. Since each ISP data connection has it's own unique A record, I have a problem because my send connector can only be configured for one dns name.

I believe the solution is to create a Send Connector for each ISP connection, along with ip addresses, firewall/nat rules and such. Then I would be able to configure the proper DNS name for each Send connector. However, I'm a little nervous to do this as I have not touched the Send connectors before and things are working right now. Does this seem like the right approach? Any tips/advice/etc appreciated! thanks...

***EDIT*** I answered my own question. I went ahead and added 3 new receive connectors, and the issue looks to be resolved.

Mike43 · **Joined:** Tue May 22, 2012 1:37 pm **Posts:** 0

if you are still getting smtp banner error here is a good blog to check for 220 smtp banner response and possibly correct the problem. It is the response received by a remote server after it connects to the receive connector of an Exchange 2010 Hub or Edge server.

to check your 220 banner in power shell:
Get-ReceiveConnector -identity "<servername>\<receive connector name>" | fl banner

Most likely your response will be blank:
Banner :

to set the banner response (mail.domain.com) to match your external records:
Set-ReceiveConnector –identity “ServerConnectorname” –Banner “220 banner text”

http://www.howexchangeworks.com/2011/06 ... -2010.html

This is a general configuration and may not apply to your environment. Please do your research before running this command in your environment. Results may vary. Make sure you have a back out plan before running the power shell command. Remember measure twice cut once.

peter@mxtoolbox.com · **Posted:** Wed May 23, 2012 7:24 am

We have posted this elsewhere on the site I'm sure, but the reverse banner check is not a hard failure, but merely a warning if you do no pass. Many people do not enforce having any banner at all.

As far as our tool is concerned, if your banner mentions your domain at all, we consider it a pass. So if you answer mail.example.com, example.com, or even example.local (which Microsoft did / does by default) and your reverse DNS resolves to anything .example.com, we call that a pass for the Diagnostic.

We are also working on a new feature for monitoring which will allow you to ignore any sub-action for a monitor if you choose to. So if you are getting a banner warning, but are happy with it, you could choose to ignore that when you monitor that server and then never receive alarms for that part of the test. Not sure when that feature will be released.

armshousegroup · **Joined:** Wed Jun 20, 2012 1:58 pm **Posts:** 0

Hi there,

I'm running a Google Apps domain (armshousegroup.co.uk) and some people are reporting that they have trouble sending emails to me - either disappear or bounce back. Most emails arrive fine though.

The only error I get is the rDNS miss-match, would this cause certain ISP's to drop emails?

My DNS is hosted with Wix and whilst I can edit most records, I don't think I can add SPF records (if that is a possible fix).

Thanks in advance for any help,
AG

wendy@mxtoolbox.com · **Posted:** Wed Jun 20, 2012 3:41 pm

Thanks for your post, yes a mismatch in DNS can cause anyone to drop your message. We would highly recommend ensuring that your rDNS is accurate.

Thanks,
Wendy

armshousegroup · **Joined:** Wed Jun 20, 2012 1:58 pm **Posts:** 0

Hi Wendy,

Thanks for the quick reply. Where do I fix the rDNS from - is that through my DNS or Google? And do you have any idea as to how specifically as all the services we use are hosted.

Many thanks,
AG

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