Thanks In Advance...
Need help to identify a Critical Issue in Live Environment.
We have Setup a Email server for out organization domain.com which is working properlly and the mail flow is also works fine with other domain. Since last week we observe that one of our client company based in UK complain that they are unable to send mails to our domain.
We start investigating and found that some mails are coming properly and some are don't even hit out Trend Micro Mail Gateway server. After 6 Hrs client get the NDR over return receipt.
Our Enviorment :-
Domain :- Domain.com
MX:- 11.12.124.15 & 200.225.112.23 (mail.domain.com) Preference 10
11.12.1247.16 & 200.225.112.24 (Gateway.domain.com) Preference 20
11.12.124.17 & 200.225.112.25 (relay.apeejaygroup.com) Preference 30
Mail Gateway Appliance :- Trend Micro InterScan Messaging Security Gateway 9.0
Client Environment:-
Domain :- clientdomain.com
MX :- brightmail by Symantec Messagelabs Cloud.
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When Client sent a mail it don't even hit any of our mail gateway server. But the user gets the Non Delivery Message. In from Brightmail NDR following error message is showing.
Delivery attempt failure - transient Attempted delivery 71/31-01753-DD55DE55 to11.12.124.15 on Mon Sep 7 09:36:23 2015Error Message: "451 4.4.2 [internal] send HELO/EHLO failed" Providing this log to the recipient, hopefully they would be able to explain this answer when we try to connect to their Server11.12.124.15
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Need help to identify that where is the issue and how to fix this so that we can start communication between our client over mail smoothly.
Regards, Koustov Choudhury
