RE: "This message has been blocked because the HELO/EHLO domain is invalid"

  • From: "Dan Klobnak" <dan.klobnak@xxxxxxxxxxxxxxxxxxxxxxx>
  • To: "[ExchangeList]" <exchangelist@xxxxxxxxxxxxx>
  • Date: Fri, 15 Jul 2005 07:32:39 -0500

I am resending this message, as I realized I had a bogus subject "RE: exchange 
Digest", and it may have been rightfully ignored. My apologies...

Hi there, MSExchange 2000 Standard SP3 on a Windows 2003 server. Our users 
received the following NDR when sending an external e-mail to one external 
domain. Not a problem with other domains; and we can reach the domain if we use 
a hotmail account or when I SMTP to it.  I am hoping to communicate with the 
other SysAdmin. Have not seen this one before, and have been doing some 
research. Based on the research, I guess I can go in a couple of different 
directions, but was curious as to your expert opinions/suggestions.

The following recipient(s) could not be reached:
'user@xxxxxxxxxxx' on 13/07/2005 9:26
You do not have permission to send to this recipient. For assistance, contact 
your system administrator.
< #5.7.1 smtp;554 5.7.1 This message has been 
blocked because the HELO/EHLO domain is invalid.>

Note: the server generating the error is our mail server. The NDR is immediate, 
and Message Tracking indicates an Event ID 1030 (NDR Generated), immediately 
after a 1020 (Started Outbound Transfer). 

Resubmitted, as I realized my subject was "RE: exchangelist digest: July 14, 
2005" and may have been rightly ignored...

Searching on:
 "You do not have permission to send to this recipient." 
Lead to options regarding being filtered by a Either on a list 
(which we tend to not believe is the case, and pur T1 Provider, Megapath, 
stated if we were ID'd as SPAMMER, they would be involved. I take that 
statement with a grain of salt).  In any event I verified our Open Relay 
status, and we're locked down. 

1.      Any websites you'd recommend to check ourselves against for further 

Another possibility may be an issue with a reverse lookup? Again, this is from 
a bunch of sources, none that I would consider authoritive, so I could be 
misinterpreting. However, our e-mail comes from our server, and our MX record's 
A record actually points to a sister company's IP, as they filter SPAM for us 
before forwarding.  There is a difference of Public IPs.
Another option maybe the fact that we do not have an SPF record in our DNS 
(something I learned about yesterday)?

Searching on:
"This message has been blocked because the HELO/EHLO domain is invalid"

Seemed to point to SMTP Virtual server setting. When I telnet to SMTP, my 
server does not match the MX record, which to be compliant with RFC 2821 seems 
to be required. The server reflects the actual server name. When I try to 
change properties of the SMTP Virtual Server to my MX record, Mail2, I can not 
verify to my internal DNS. I don't want to go to the issue of changing my 
server's name, and I am thinking I can not have two entries within DNS pointing 
to the same IP, or is there a way to accommodate? 

Other option, modify my MX record to be reflect my server name?

I admit, I am treading some deep water here for me. Since we're successful with 
99.99 of other external e-mails, it is appealing to say it's the other side 
(the "been blocked because the HELO/EHLO domain is invalid" certainly is not 
saying which domain is invalid. When I SMTP their mail server,, their server name is simply, so they are not 
'compliant' either.). However, since we have a few loose ends on our side, I'd 
like to tighten us up, as I imagine the ongoing battle with SPAM will simply be 
cause more of these errors.

Any other ideas, thoughts, would be GREATLY appreciated.

I can't seem to find anything regarding these search strings at MS support 
either, so I assume I'm searching incorrectly. Thanks, Dan

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