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Email Protocols





Interactions between email servers and clients are governed by email protocols. The three most common email protocols are POP, IMAP and MAPI. Most email software operates under one of these (and many products support more than one).  The correct protocol must be selected, and correctly configured, if you want your email account to work.

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Hi All,

Can anyone here please let me know what do I need to do in order to successfully cutting over the Anti Spam solution from onPremise Linux VM into the Cloud Solution with no data loss or user email flow interruptions?

As at the moment on my Exchange 2013, the Send Connector Smarthosts listing the local IP address for the 2x Linux VMs.

Do I just change it to the Public IP address of the Cloud Anti-Spam provider ?

Note: My Public DNS server is running on my On-premise Windows Server 2008 R2 VMs.

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Dear Wizards, when I changed my display name in OWA - Exchange 2016 ono-premises, this error appeared. Can you please explain and suggest? Many thanks.

Env: Exchange 2016 - Win server 2012R2
We are having an issue where users are not receiving delayed delivery status emails but they are receiving failed delivery notifications.  The option is set to notify sender when message is delayed by one hour but no one ever receives it.  Any ideas?
Our client (a sort of golf travel company) in the UK regularly sends out email worldwide to their clients. They are now receiving bounce-backs in German, making it difficult for my client to resolve them. The user sending the orginal emails is

I have contacted  the ISP (Fasthosts in the UK) and they understandably say "This would only happen if the e-mail you are sending to is hosted on a German server as the bounce back is sent from the server rejecting the e-mail." however, our client receives these from all over the world always with the same formatting, so they seem to be coming from the same generating program, if not the same server?

I attach some of the bounce messages (they're in Outlook Item file format).

I suppose the other issue is what are these, or what's causing, the bounce-backs in the first place?

I am sure those of you who "enjoy" trawling through email bounce headers will find this a fun challenge :-)

I’d like to reduce the Spoofing SPAM by enabling DKIM and DMARC, so I need your assistance in how to implement this to all of my Exchange Server accepted email domains ?

Note: I am managing my Public DNS server On Premise running on the Windows Server box, so I can have access to the records myself.

From my understanding, I can just add the below entry:

DKIM: Create a CNAME record for with this value:
SPF: Create a TXT record for with: v=spf1 ?all
DMARC: … not sure

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But I need further detailed steps if any.

Dear Experts, I am wondering if we can monitor the usage of users' mailboxes in Exchange 2016 Server (Win2012R2), just like we usually monitor servers, network devices,...; so that we can have proper actions when someone nearly reach his/her quota.

Do you know any tool or procedures to do that? Many thanks in advance

Can anyone here please assist me with the below issue where my internal user gets NDR with the below error message:

Diagnostic information for administrators:
Generating server:
Remote Server returned '< #5.7.1 smtp; 554 5.7.1 Error: need authentication from>

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Any help would be greatly appreciated.

Dear Experts, can we create a distribution group which contains email accounts from different domains (than the server's domain)? If so, how can we configure it?

Example: Exchange 2016 server for domain

Can we create a distribution group that includes?
Dear Experts, does anyone know how to monitor the email flows from users (like statistics, how many email per day, per hours each user send/receive,..) in Exchange 2016 environment? (Server 2012R2)

Besides, is there any option so that we can limit that number, to avoid hacker can login to email account and send huge number of spam emails to outside, leading to blacklist our domain?
Dear guys, is there any public black list like this? we are building our own Exchange server and want a list of black domains; so that we can configure antispam agent on Exchange to block them.
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Dear Experts, can we delete the log files in %ExchangeInstallationPath%\Mailbox\DB ?

We observed and saw that they increases everyday. If we cannot delete them, how can we reduce their size?

Env: Exchange 2016 Mailbox server, Window server 2012 R2
Anyone know the SMTP authentication for   I'm also not well versed in Apple Mail client so I may be doing something wrong.  I referenced below but I don't see SMTP authentication... My options are External, Kerberos, NTLM, MD5, and Password.  Also, do I need need a IMAP path prefix ?
Dear Team, we are suffering the slow problem of Email Exchange 2016: Send from Exchange server is OK, but receive is slow; which ever have or does not have attachments.

We have Avast installed in Exchange server, everything in default mode, not sure which Exchange part should be added to AV's exclusion.

Is there any other way for tuning or increasing the speed (except increase the bandwitdth, we are in Leased line link: 30 Mb/s International + 50 Mb/s Domestic)?

Many thanks as always!
Can one add a hyperlink to fields that when clicked not only creates an email but can fill in the other email fields like CC, Subject, and Body?

I have done this in excel, but not sure if the hyperlink format formula editor in crystal reports can handle this.

What I did in excel:

HYPERLINK("mailto:"&$A$1&"?cc="&$A$2&"&subject=TRD INQ: "&B9&"  |  "&E9&"  |  "&F9&"%  |  "&I9&"  |  "&H9&" &body=CUSIP: "&B9&"%0AAmount:%0AAccount:%0ASub Account:%0A%0ADealer: "&Y9,"SEND")

this excel formula handles creating the email and populating the To, CC, Subject, Body.
I have an enormous problem about my disk quota .
Everyday tons of emails enter my mailboxes
I have a plan to pull all my email to sync in local folder. So my i can freed my corporate email
Are there any tutorial to pull all of my corporate email via Thunderbird ?
POP3 or IMAP kindly accepted


Romi Nur

We have a client who has just had a DKIM domainkey setup for them. Unfortunately some emails are not getting through to the end users (especially if using Mimecast mail servers).

We have been doing some testing and have found that:
Emails that do not have an attached file - it pass the DKIM checks.
If emails have attached documents, they seem to pass OK as well.
If emails have got an attached email that was originally from the sender, it passes OK
If an email has an attached email from a third party (that has originally been changed with DKIM) it fails the DKIM test on our/the recipients servers. This has happened to us and we use exchange online servers.

When it fails it says dkim=fail (body hash did not verify)

They have a valid SPF record also setup and every email through the testing procedure seems to pass on the SPF checks without any failures.

There is no DMARC record setup yet, but as far as I can see this is the next step after we have got DKIM working correctly.

Unfortunately our client who is having this problem quite often forward a lot of emails during their working day so need this resolving.

Any help would be appreciated.
Dear Guys, please assist this scenario:
- Action: We changeed Email server from Gmail to Exchange 2016 On-premise, so we had to change the domain records in Domain control panel. We changed TXT, MX, @, mail records.

- Problem: After changes, the new Exchange server worked (send/receive emails) normally as expected, however we realized that we could still login to Gmail account, Google Drive and sent emails (but could not receive emails)

So can you please explain?

outlook email alerts not coming. How keep alerts so that when email comes popup comes and also preferably some sound comes?
please advise
Dear, I tried but could not start this service. Does anyone get this error before? Can you please help?
Many thanks in advance,
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After reboot, I got this error in Exchange Management Console, also I could not login to OWA, it showed blank page when I entered correct username/password.

All Exchange services are running. Environment: Exchange 2016, Window Server 2012R2

Can anyone help, please?
"The Name on the security certificate is invalid or does not match the name of the site"

We have a user who is experiencing this error when traveling . Problem only occurs when connecting to MS Outlook via a hotel or public wifi, but not all of the time.

Similar issue occurred two weeks ago on the same user's cellular phone (as well as a coworker he was traveling with). Both employees were out of state when this happened

  • We have other employees who travel out of state who have reporting nothing
  • We are on Exchange 2010
  • User is on Outlook 2010 client
  • Validated with Godaddy, our certificate issuer that the certificate is perfectly fine
  • Validated with MXToolbox that mail autodiscover resolves fine
  • User connects perfectly fine from home, which is also out of state (remote worker)
  • Issue began two weeks ago, making this problem seem like more than a coincidence

If there's anything else I should be looking at, I'd love to know! TY -Dave
Does Migration Wiz migrate all emails, calendar items, contacts, tasks, etc. from Gmail into Office 365?

Or does it only migrate emails?
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Dear Guys, we are deploying Exchange mail server. We knew that the Mail server must be published with an public IP address (and registered with A, MX, TXT records) but is it mandatory for an Active Directory (of mail users) Server to also have an public IP address and to be registered (by A record) in domain control panel?

Many thanks in advance,
When I email users from one particular company domain (and only that domain) they get my email from my company domain email, but when they reply (and also if they just directly write to me)  it doesn't come to my company email, even though on their outbound email that is what shows as the 'to', instead it arrives in my personal yahoo email, even though the sender couldn't even possibly know what my personal yahoo email is.

This happens for any sender from this particular company to me, but the same doesn't happen when that company sends emails to anyone else in my company, they work fine. They also say they never had this problem with anyone else. I do not have any forwarding of any kind of redirect set up in my email system. None of my other colleagues have any issues receiving emails from this company.

Looking at the header of the message I receive it shows

X-Apparently-To:; Thu, 27 Jul 2017 07:39:28 +0000
Return-Path: <>
Received-SPF: pass (domain of designates 104.4xxxx as permitted sender)

Authentication-Results:; domainkeys=neutral (no sig);; dkim=pass (ok)
Received: from  (EHLO (xxxx)
 by with SMTPS; Thu, 27 Jul 2017 07:39:27 +0000
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=selector1-sender-com;

From: Asxxxxx…

Email Protocols





Interactions between email servers and clients are governed by email protocols. The three most common email protocols are POP, IMAP and MAPI. Most email software operates under one of these (and many products support more than one).  The correct protocol must be selected, and correctly configured, if you want your email account to work.