• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 1057
  • Last Modified:

Unable to send email to a particular domain

Hi

We have an Exchange server 2010 Environment mixed with Exchange 2003.
There is a domain which is external to where we are not able to send emails.
But if we try to send an email from a GMAIL, Yahoo or Hotmail Account, the recipient receives.

Lets say the domain external.com is sending an email to us at internal.com we are receiving it.

We have Postini also as our external Spam and Filtering Gateway and we see that the messages are getting relayed or R-Injected if tried to send from anyone@internal.com to anyone@external.com.

I tried checking this issue on the website www.mxtoolbox.com and found that the logs say that the server at external.com accepts only messages if the SMTP Authentication is enabled.

But as i recall, this option is available only if POP3 accounts are configured to put a tick mark in the account settings to say that the server requires SMTP Authentication.

I am able to telnet to the mx record hostname successfully from the SMTP / Transport servers for external.com

but in Exchange i am not sure, i have tried everything of my knowledge.

Please assist on this issue.


Please note: Earlier we were able to send emails to this domain without any issue.
0
brandsco
Asked:
brandsco
  • 4
  • 2
  • 2
  • +4
1 Solution
 
scriven_jCommented:
Do a blacklist check on MXTOOLBOX as it sounds like you might be blacklisted.  If this is the case, some domains will block all mail from your domain.
0
 
Vinod PawarCommented:
As you said external domain recives mail from gmail yahoo but not your domain you can check with reciept delivery for NDR message for checking issue. if its authentication issue you need to check with recive connector on exchange side.
also check if your external face exchange or SMTP server IP is allowed as whitelisted IP on external domain
0
 
Manpreet SIngh KhatraSolutions Architect, Project LeadCommented:
Have you allowed "Anonymous Users" checked on the Receive connector on the E2k10 server ?
How does the email flow happen ?
If this is not the actual domain you have then you need to have it added as "Accepted Domain".

- Rancy
0
Creating Active Directory Users from a Text File

If your organization has a need to mass-create AD user accounts, watch this video to see how its done without the need for scripting or other unnecessary complexities.

 
Svet PaperovIT ManagerCommented:
If I understand correctly, you are using Postini Outbound Services to filter the messages sent from your organization.

If that is the case, there is no worries you are not blacklisted. But you will have to verify how the Postini Outbound Connector is configured because it's Postini who talks to external.com an not your Exchange.

Postini has sevaral connection methods that can be used (see p. 525 of Postini Admin Guide or http://www.google.com/support/enterprise/static/postini/docs/admin/en/admin_ee_cu/outbound.26.10.html#4612177): if you are using TLS First or TLS Only that could cause som delivery problems. I would suggest switching to SMTP only without encryption and testing.
0
 
suriyaehnopCommented:
Could you share NDR message?
0
 
brandscoAuthor Commented:
Our Domain internal.com is not blacklisted as per MXToolbox.

Postini TLS Settings are configured as below

1. Choose how the email protection service accepts outbound messages from your mail server. ------- Accept SMTP & TLS

2. Choose how the email protection service sends your outbound message to recipient mail servers. ------- Send Only SMTP (No TLS encryption, all messages delivered via SMTP.)

See NDR Message as below,

From: System Administrator
Sent: 20 August 2012 09:15
To: John Smith
Subject: Undeliverable: RE: test


Your message did not reach some or all of the intended recipients.

      Subject:      RE: test
      Sent:      20/08/2012 09:15

The following recipient(s) cannot be reached:

      person@external.com on 20/08/2012 09:15
            There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            <smtpserver.corp.internal.com #5.5.0 smtp;550 MX records inaccessible for too long for domain:external.com - psmtp>


Please explain the Receive Connector part.. Is that on the Hub Transport Server?

and also one more thing is that, we did not make any changes on Postini as well as our exchange environment. earlier it was working. ( :-) i understand in our field problems suddenly arise) so i am tryin to drill down where the issue is exactly
0
 
Nagendra Pratap SinghCommented:
ping smtpserver.corp.internal.com .

it may not be accessible from the internet or some firewall may have blocked it.
0
 
brandscoAuthor Commented:
npsingh123 - we are using Postini SMTP Gateway and so smtpserver.corp.internal.com wll not be reachable.. the postini SMTPs are reachable via internet.
0
 
suriyaehnopCommented:
nslookupCould you do nslookup for mx records for corp.internal.com from your Postini something like this on screenshot.

There is communication issue between your Postini with receiver's email server. Could you try this use another account (gmail, yahoo) send an email to receiver and verify if email able to reach and asked receiver to trust your Positini IP address
0
 
brandscoAuthor Commented:
Yes i am able to do nslookup and mx records are also there for the internal.com domain.
I am able to telnet to those mx records hostnames from a standalone internet pc.

@Rancy - Can you please elaborate the Receive Connector part of your comment.

Thanks
0
 
Manpreet SIngh KhatraSolutions Architect, Project LeadCommented:
smtpserver.corp.internal.com #5.5.0 smtp;550 MX records inaccessible for too long for domain:external.com - psmtp

Unable to send email to a particular domain and that too your getting the above NDR clearly says issue at the recipient end nothing to do with your environment.

Can you send email to the external recipient from Public domain ?
Check with recipient domain if they have made some changes to their firewall and need to white list you or something ?
Do you have some kind of direct routing or information to send emails to that domain ?

Receive connector would only come into picture if you cant receive emails from any External or Public domain users :)

- Rancy
0
 
Svet PaperovIT ManagerCommented:
I would suggest a small test: try bypassing Postini Outbound Services for that domain. You can achieve that by configuring an additional Sent Connector where you will specify external.com in Address space tab with lower cost than the default SMTP connector sending the e-mails to Postini.

In that way you will know where to look for the problem: your server or Postini
0
 
brandscoAuthor Commented:
@Rancy - Yes, I agreed that according to the NDR it says that external.com is not accepting messages from our domain.

From Gmail, Yahoo, Hotmail and other domains like ourcompanyno1.com, ourcompanyno2.com, ourcompanyno3.com... They are working as well.

I will also check with the recipient domain if there are any policies or anything new been done. I will get back to you shortly.
0

Featured Post

 The Evil-ution of Network Security Threats

What are the hacks that forever changed the security industry? To answer that question, we created an exciting new eBook that takes you on a trip through hacking history. It explores the top hacks from the 80s to 2010s, why they mattered, and how the security industry responded.

  • 4
  • 2
  • 2
  • +4
Tackle projects and never again get stuck behind a technical roadblock.
Join Now