Mail server hostname greeting warning

Posted on 2009-05-08
Last Modified: 2012-05-06
I am in the process of setting up exchange 2007 on SBS 2008 server.  Brand new setup no migration.  I have exchange configured correctly as I can send and receive email with no problems internally and externally.  In the exchange 07 you have to manually create send and receive connectors and based on some documentation I read it should be set as

Well when i run my dns report I get the following:
WARNING: One or more of your mailservers is claiming to be a host other than what it really is (the SMTP greeting should be a 3-digit code, followed by a space or a dash, then the host name). If your mailserver sends out E-mail using this domain in its EHLO or HELO, your E-mail might get blocked by anti-spam software. This is also a technical violation of RFC821 4.3 (and RFC2821 4.3.1). Note that the hostname given in the SMTP greeting should have an A record pointing back to the same server. Note that this one test may use a cached DNS record. claims to be non-existent host <br /> 220 Microsoft ESMTP MAIL Service ready at Fri, 8 May 2009 20:22:00 -0400 <br />

As you see in the last line the names match.  The A record is created properly or otherwise it would receive messages right.  Any idea what would cause that?

I can send and receive just fine, my only reason in posting this is that in the next couple of weeks, something isn't set right with outgoing mail and the company gets put on a blacklist.

Let me know if anyone has seen this before.

Question by:jbmos2333
  • 2

Accepted Solution

DTAHARLEV earned 500 total points
ID: 24342174
many spam filters today do a reverse lookup, to verify the IP address you're coming from does in fact resolve to the FQDN you are saying you are. in your case, you show up as "", which resolves to IP address However, when you run a REVERSE lookup on that IP address, you don't get, but you actually get:

You need to contact comcast business and ask them to create a reverse record, which resolves to It may take some time to get to someone who knows what they're doing, but once you do they'll set it up for you in two seconds.

Author Comment

ID: 24343748
I will give them a call and see if that solves the issue.  

Expert Comment

ID: 24343860
be persistent... with time warner in new york it takes hours until you get to the right business-tech-support-dedicated-cable-guy, but once you get to them, he says "oh, no problem, give me a minute" and after five minutes it's propagated and emails to aol work.
LVL 65

Expert Comment

ID: 24346468
Be aware that Exchange 2007 fails the tests done by web sites on SMTP headers.
This is because Exchange announces itself differently on incoming and outbound email. When it comes to messages being flagged it is only the setting on the Send Connector for outbound email that is important, which web based testing tools cannot see.

Exchange 2007 only supports the server's real name, NETBIOS name or blank as the FQDN on the receive connector, so you cannot "fix" the problem.

If you can create the host name, then do so, along with a reverse DNS record. However if you are using another hostname/reverse DNS combination then that FQDN needs to set on the Send Connector.


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