My company has an Exchange Sever 2013. It stoppde to send/to receive external emails

We only can send / receive internal emails.
I checked the inbound - outbound connectors : the server ip is correct

The CNAME record points to Microsoft EOP:   and
The MX record :xxxxx
please help
francisco SotoAsked:
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sending & receiving uses different facilities so treat them as separate issues until proved otherwise. bit odd theyd both at the same time tho....

firstly, has anyone (internal or external) had a boundback? these would be really useful to start with.

secondly, do you use any external mail filtering or smarthosts?

has you internet/firewall been changed or amended?
francisco SotoAuthor Commented:
yes we get bounback.

Received: from ( by ( with Microsoft SMTP Server
 (TLS) id 15.0.712.24 via Mailbox Transport; Wed, 27 Aug 2014 16:32:16 -0400
MIME-Version: 1.0
From: Microsoft Outlook
To: <>
Date: Wed, 27 Aug 2014 16:32:16 -0400
Content-Type: multipart/report; report-type=delivery-status;
X-MS-Exchange-Organization-SCL: -1
Content-Language: en-US
Message-ID: <>
In-Reply-To: <>
References: <>
Thread-Topic: test
Thread-Index: AQHPwhJT4WFlcZqVLkSeZ3GSy4r+QJvk59ZN
Subject: Delivery delayed:test
Auto-Submitted: auto-replied
X-MS-Exchange-Organization-AuthAs: Internal
X-MS-Exchange-Organization-AuthMechanism: 05
X-MS-Exchange-Organization-Network-Message-Id: 7b0aeb8b-b5b3-45af-f6b7-08d1904d2013
X-MS-Exchange-Organization-AVStamp-Enterprise: 1.0
Return-Path: <>
the external mail filtering is Microsoft Online Protection
the firewall is managed for level3. no changes
francisco SotoAuthor Commented:
Delivery has failed to these recipients or groups:

'' (
 Your message wasn't delivered due to a permission or security issue. It may have been rejected by a moderator, the address may only accept email from certain senders, or another restriction may be preventing delivery.

The following organization rejected your message:
How do you know if your security is working?

Protecting your business doesn’t have to mean sifting through endless alerts and notifications. With WatchGuard Total Security Suite, you can feel confident that your business is secure, meaning you can get back to the things that have been sitting on your to-do list.

you haven't specific whether these bouncebacks are incoming or outgoing.

could you also please advise if is your server or someone elses?
francisco SotoAuthor Commented:
yes, this is our server.
both incoming and outgoing
we have internal mail flow perfect.
still a bit odd really. it is very rare that you would get the same issue both incoming and outgoing. is the bounceback message the same?

lets look at one issue at a time....

things to check on incoming:
receive connector - anonymous messages enabled
mailbox/disty group - 'require all senders to be authenticated' uncheckd
firewall - check port 25 goes to correct server

try running a manual test to confirm if traffic flows ok.
francisco SotoAuthor Commented:
Issue fixed. It was a firewall issue.
From: <>
Sent: Thursday, September 4, 2014 4:20 PM
To: Francisco Soto

Subject: RE: Level (3) Ticket #: 8302553, Dual Temp Co. Inc.-Dual Temp Company, Inc., Ticket Updated, Customer Ticket ID:

Good afternoon,

The inbound nat object was not being called upon properly, once we adjusted the rule it allowed natting to take place properly. It was configured so that was reaching out over the external interface and when the traffic was coming back in the natted object was not being activated.

Very respectfully,

Charles Eakes
Level 3 Communications

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francisco SotoAuthor Commented:
I've requested that this question be closed as follows:

Accepted answer: 0 points for francisco Soto's comment #a40359502

for the following reason:

Bit  unfair to just accept your own solution there mate. In addition to the help I offered I also pointed you in the direction of the firewall in post 40322154.
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