Solved

Possibly forged hostname

Posted on 2013-11-07
12
112 Views
Last Modified: 2016-07-11
I'm getting a rejected email from a specific domain only, the rejection message is: "451 4.1.8 Possibly forged hostname for 64.132.162.194 (in reply to RCPT TO command)".

I have only one exchanged server 2010 and barracuda at front. I have setup sendconnectors that the smarthost point to barracuda as a smarthost, under sendconnector network properties.

Domain records are at Register.com. 64.132.162.194 resolves to barracuda.trendsinternational.com and reverse records also resolves to barracuda.trendsinternational.com.

Again, there is only one customer rejecting, our emails.

thank you very much!
0
Comment
Question by:paco1969
  • 5
  • 5
12 Comments
 
LVL 63

Accepted Solution

by:
Simon Butler (Sembee) earned 500 total points
ID: 39630361
If there is a problem, it is with the appliance, as that is what the external server will see.

Do the test as outlined here:
http://cbl.abuseat.org/helocheck.html

That will verify how your appliance is announcing itself to the world.

Simon.
0
 

Author Comment

by:paco1969
ID: 39630528
Simon, thank you for your response. I have tried your suggestion and this is what I got back RCPT TO: helocheck@helocheck.abuseat.org
550 5.7.1 Unable to relay
0
 

Author Comment

by:paco1969
ID: 39630541
Delivery has failed to these recipients or groups:

helocheck@helocheck.abuseat.org
A problem occurred during the delivery of this message to this e-mail address. Try sending this message again. If the problem continues, please contact your helpdesk.


and I got this from outlook: Generating server: barracuda.trendsinternational.com

helocheck@helocheck.abuseat.org
#< #5.0.0 X-Spam-&-Virus-Firewall; host helocheck.abuseat.org[54.245.112.115] said: 550 *** The HELO for IP address 64.132.162.194 was 'barracuda.trendsinternational.com' (valid syntax) *** (in reply to RCPT TO command)> #SMTP#
0
Problems using Powershell and Active Directory?

Managing Active Directory does not always have to be complicated.  If you are spending more time trying instead of doing, then it's time to look at something else. For nearly 20 years, AD admins around the world have used one tool for day-to-day AD management: Hyena. Discover why

 
LVL 63

Expert Comment

by:Simon Butler (Sembee)
ID: 39630648
The NDR is correct. If the host name is valid in the NDR and is what you expect then everything would appear to be correct - it has to be a false positive on the other side.

Simon.
0
 

Author Comment

by:paco1969
ID: 39630921
Simon, an observation: when I check MX lookup for trendsinternational.com on MXToolBox I get: Pref            Hostname                                       IP                 Address       TTL       
         0          exchange.trendsinternational.com       64.132.162.194       24 hrs
       10          mail.trendsinternational.com       64.132.162.194       24 hrs       
Also, I want to thank you very much for your assistance.
0
 
LVL 63

Assisted Solution

by:Simon Butler (Sembee)
Simon Butler (Sembee) earned 500 total points
ID: 39630939
It would have to be a very picky site to reject on that basis. It would do no harm to replace the mail one with the actual host name and delete the 0 one completely.

Simon.
0
 

Author Comment

by:paco1969
ID: 39631011
you mean replace it with the exchange host name or barracuda name?
0
 
LVL 63

Assisted Solution

by:Simon Butler (Sembee)
Simon Butler (Sembee) earned 500 total points
ID: 39631244
The appliance, because that is what the internet sees. Exchange is behind the appliance, but the internet doesn't care.

Simon.
0
 

Author Comment

by:paco1969
ID: 39631263
Thank you simon, you have been a great help!!
0
 
LVL 63

Expert Comment

by:Simon Butler (Sembee)
ID: 41704157
Object. I have answered the question.

ID: 39631244
ID: 39630939
ID: 39630361
0

Featured Post

Is Your AD Toolbox Looking More Like a Toybox?

Managing Active Directory can get complicated.  Often, the native tools for managing AD are just not up to the task.  The largest Active Directory installations in the world have relied on one tool to manage their day-to-day administration tasks: Hyena. Start your trial today.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article lists the top 5 free OST to PST Converter Tools. These tools save a lot of time for users when they want to convert OST to PST after their exchange server is no longer available or some other critical issue with exchange server or impor…
Read this checklist to learn more about the 15 things you should never include in an email signature.
The video tutorial explains the basics of the Exchange server Database Availability groups. The components of this video include: 1. Automatic Failover 2. Failover Clustering 3. Active Manager
This video shows how to quickly and easily add an email signature for all users on Exchange 2016. The resulting signature is applied on a server level by Exchange Online. The email signature template has been downloaded from: www.mail-signatures…

777 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question