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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Dear EE

Please can someone tell me what's the difference between the "From" and "X-Sender" field in message header?

We recently had a spoof and phising attempt on one of your users.

I have SPF in place and it works but it didnt stop this email because the X-Sender address is not that of my domain. My SMTP domain is

Please see image:

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Where within the Gmail admin console can the external DNS mail exchange (MX) records be changed for an organization using Gmail for its email?
We have recently migrated from Exchange 2007 to Office/Exchange365. Since migration we have received a number of email rejections on one specific email indicating "your email program added invalid characters (bare line feed characters) into a message you sent".

The email itself comes from an HTML template and generated in Microsoft Dynamics AX. This is directed email to customers and is consistently accepted by some downstream providers (eg gmail, Hotmail) but not others (eg Yahoo, Comcast).

The HTML code that comprises the body text has been scrutinized and does not contain any bare LF's, nor has it changed since long before the migration.

Support from Microsoft, Yahoo and Comcast has been of little use (for the most part unwilling to engage other than throw out generalities to get you off the phone).

Key facts;
- email was working prior to (Exchange 2007 to Office365) migration
- other (text) email to affected customers is delivered without issue (ie limited to one HTML email)
- originating email has been checked for bare LF's

As this email was working previously I have the following questions;
- have you seen and resolved similar issues?
- As this was working previously I am wondering if Exchange 2007 stripped out bare LF's in order to fix (my understanding is that Office 365 was but stopped doing so).

Please do not suggest online articles found by Google searches unless you feel there is something very specific we can look at. We have searched …
I would like to make a parse of postfix mail log in an HTML/PHP page with a search bar and then creating a dynamic table with all these tags. when the table is done I should be able to click on the "Date" and another page should open with others info about that log *(2)

I will copy an example of a log

search: from: ...... to: ...... date: from: .... to: ....

Eg Table example: Date | time | from: Jack | to: John | status:


status detail

809318:Jul 11 14:13:50 amail-2014 postfix/smtpd[17127]: 78F5E83F28:[]
809320:Jul 11 14:13:50 amail-2014 postfix/cleanup[18135]: 78F5E83F28: message-id=<>
809324:Jul 11 14:13:50 amail-2014 postfix/qmgr[27711]: 78F5E83F28: from=<NO-REPLY@MOLEX.COM>, size=30390, nrcpt=1 (queue active)
809325:Jul 11 14:13:50 amail-2014 postfix/smtp[11782]: 78F5E83F28: to=<*****@SYLEX.SK>,[]:25, delay=0.73, delays=0.59/0/0.01/0.13, dsn=2.6.0, status=sent (250 2.6.0 <> [InternalId=50607599648815,] Queued mail for delivery)
809326:Jul 11 14:13:50 amail-2014 postfix/qmgr[27711]: 78F5E83F28: removed
809323:Jul 11 14:13:50 amail-2014 KLMS: not processed: …
Dear All, I found this link to bulk import .PST file to Exchange users' accounts:, but not sure if the .PST can come from different domains than the Exchange server's?

For example:
- New Exchange server's domain is
- PST files include email data from Old domain

Can we import it? Does anyone can help please?
I got a mail from was it real or not please tell me
I have one client that cannot email me.. They receive a bounced back message saying;

550 Verification Failed
No such user here
Sender verification failed

I can however email them. But they cannot reply.

None of their emails from their domain will come through, however I have been guaranteed from my ISP (crazy domains) that there are no blocks on my end. However i do know of another company who are with crazy domains are experiencing the same problem with the server  

As I run my ow  business, my only option is to change hosting companies in the hope that works.

Would love an easier fix
Hi All,

May I know where shall I manually add the below entry if I handle the Public DNS using Windows Server box in my DMZ ?

DKIM: Create a CNAME record for with this value:

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SPF: Create a TXT record for with:
v=spf1 ?all

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What is the risk or issue when implementing it during the business hours ?
I am trying to setup subscriptions through our reports server generate reports and have them automatically emailed to external addresses.
I am using SQL Server 2012
Reporting Services Configuration Manager
Email settings:
Sender address:
current smtp delivery method: use smtp server
smtp server:

WE do not have a local smtp server setup so if I can use google smtp or some other method to send mails from the reports server that would be great.

Thanks for your assistance:

recently my mail relay server experiencing incoming mail delayed from, as i see online forums, MS recently have stopped using TLS 1.0 authentication and only supports TLS 1.1 and 1.2, but not all of their servers but 75% of it, but my mail relay server doesn't have any TLS enabled, so is this can be the issue?

all the mails from other mail servers receive without any issue.

My mail relay server is CentOS 6.5 , (no Grey list enebled, no SPAM filter, no TLS enabled)
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Facing an issue with one company, that I can't receive email from them !!
Wwe have our own mail server as they do , they have Exchange Server as they mentioned,and we have SPAM Filter Appliance but the email never reaches SPAM Filter in order to be checked and sent to Our Mail Server.
Our Domain is hosted  with hosting company and they are pointing MX Record to our public IPs .

What are the steps to troubleshoot the issue ?

Thank You
Dear All,

I have a question. When my clients send their transactional emails using my provided SMTPS, I process the MTA logs to generate bounces and track emails. I need some guidance here, how would I put my web application in the middle of MTA and the client so if any client sends any transactional email using the provided smtp, it pushes the email to my application first and then my application pushes it to the mta after filtering it.

Thank You
Like the title says, we are missing Outlook 2013 calendar entries and contacts.

We are not using Exchange, but we are using an ost file. I did an Outlook scanpst, and Outlook repair. Some of the messages were gone, so I deleted the .ost file to allow it to rebuild. Although all the email messages have returned, the Outlook Calendar entries and contacts are gone. How do we get those back? This is just one PC that is affected. Thanks.
I am receiving the following error when truing to setup Microsoft Exchange 2013 on a new server. I have followed all of the instructions noted in Microsoft's guide:
However when I run the installer it throws this error when setting up the "Mailbox role: Transport service."

The following error was generated when "$error.Clear(); 
            if ($RoleProductPlatform -eq "amd64")
                $useAttachMode = $false;
                $fastInstallConfigPath = Join-Path -Path $RoleBinPath -ChildPath "Search\Ceres\Installer";
                $command = Join-Path -Path $fastInstallConfigPath -ChildPath "InstallConfig.ps1";
                $fastDefaultDataFolderPath = Join-Path -Path $RoleBinPath -ChildPath "Search\Ceres\HostController\Data";
                $dataFolderPath = $fastDefaultDataFolderPath;
                if ([System.IO.Directory]::Exists($fastDefaultDataFolderPath))
                    $useAttachMode = $true;
                    if ($RoleIsDatacenter -eq $true)
                        $preferredDataFolderPathRoot = "D:\";
                        if ([System.IO.Directory]::Exists($preferredDataFolderPathRoot))
                            $dataFolderPath = Join-Path -Path 

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Hi All,

Our environment runs exchange 2010. Recently we have found that we are unable to set up SMTP on devices (scan to email on copiers, email notifications on various things). Details are entered in correctly at the device but the test always fails with a generic error (unable to send email) etc.

Some other devices on the same network seem to be able to send SMTP notifications without issue (e.g. our UPS). If I copy the exact SMTP details in a device that isn't working, to one that is. The email sends, indicating to me that the actual settings are ok?

The only reason I can think of to cause this would be that some devices require something additional that our Exchange Server doesn't have configured?

We have no known issues with our Exchange server. I've had a look at "Receive Connectors" in Exchange, and tried adding in a new receive connector for the IP address of a device that isn't working, but it doesn't seem to solve the issue.

What should I be looking at to ensure that all devices within our network can communicate via SMTP?

I have tried testing SMTP using a few tools, using "bmail" from here:

I can successfully send an email from any made up address to a valid address in our organisation using the below example command:

C:\> bmail -s MyServer -t -f -b "This is a test" -h -a "This is the subject"

That works.

Using TELNET and …
I changed the password on a account and now it is failing.  It keeps asking me to put in the log in and password and when it tests an email, it fails to connect to server.  I have tried deleting the email and reinstalling it.  It won't reinstall it.  I have tried using the old password.  Nothing is working.
I am setting up an email account on Outlook 2016 with IMAP server settings.  When I delete a message I want it to go to the delete or trash folder but remain available for future reference.  Is there a difference between trash & deleted folders?  I have UNchecked both boxes in the "deleted items" for internet email settings".  Thanks in advance for your thoughts!
I have a Server 2012 R2 with Intel Active System Console running.
I want to receive emails on Critical Events.
I need to configure Mail Server Address, User ID, Password and Recipient Email ID.
I use my ISP's SMTP server address for the Mail Server Address.
It doesn't require authentication but I am forced to put in a User ID and Password.
There are no options for configuring ports or encryption.

What User ID and Password do I use? The one I use to log into Intel Active System Console or one for the email server?

How do I test this is working?
I have Dropcam (now Nest) forward mail to three different email addresses.  Often, one relay entity is very slow (just now, 111 minutes).  This is usually ""  Why and what should I do about it?
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I want my mail address back
User get the error message attached

The laptop has been formatted but the issue still exists. It happens only to this user
I have postfix installed on a fedora linux server.  It works for the most part.  I can receive mail and reply via webmail.   It does not work for mail clients.  It will receive mail okay but you cannot sent outgoing via my mail server.  
Plus gmail will not accept my emails because I do not have encryption set up.    Post fix was installed by another admin and I do not want to lose the functionality I have but I need to get up to speed with encryption and being able to send emails from an email client.  
Help please.
I have a custom developed (Mail Service Process) that gathers notification information from various customers, and then builds a notification email and then sends that email through a smtp server (mail chimp).

Some times my (MPS) server or process fails and the emails stop being sent out.  I need to know when we stop sending out emails.  Unfortunately, the server is still running, and the Service is still running, it's just not sending the emails.

I'm thinking I could send (on a schedule, like every 5 or 15 minutes) a genetic "status" email to somewhere external that is watching, and will notify me that the status emails are not showing up, rather than me finding out when a customer realizes they are not getting emails.

Sort of like a deadman switch for outgoing email.

Does anyone know of such a service?  I have seen services that do full send/recv email account verification, but that is not the same.
Hello Expert,
                       In our CRM software application, we track if an email is opened by sending  an image. But for gmail and yahoo, from recent past, we are not able to track the open status and update in our database.

we use below link to check the mail status:
<img  style=\"background-image:url('"+ DomainName + "MailStatus.aspx?type=open&MailKey=" + mailKey + "&DB=" + Session["PMSFolder"] +"');\" src=\"\">"

This code works in some mail servers but in Gmail and Yahoo mail servers.

URL we send:   src=” Images/e-con-logo.png "

When we check after opening the image in the inspect element. it contains exact src path in some mail servers but in gmail some additional content is added  in src as shown below below:

src=" Images/e-con-logo.png ">

Please help us address this to track email users.

I have a task to urgently install POP3 service for and existing exim installation on Debian 8.
Which POP3 server is the best? Please link configuration guide if possible.

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.