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Email Servers





Within Internet message handling services (MHS), a message transfer agent or mail transfer agent (MTA) or mail relay is software that transfers electronic mail messages from one computer to another using a client–server application architecture. A MTA implements both the client (sending) and server (receiving) portions of the Simple Mail Transfer Protocol (SMTP). The terms mail server, mail exchanger, and MX host may also refer to a computer performing the MTA function. The Domain Name System (DNS) associates a mail server to a domain with mail exchanger (MX) resource records containing the domain name of a host providing MTA services.

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I am getting emails from my own email account advising I have been hacked, they have my password (albeit an old one) and will divulge information about me.

I have changed passwords for every single login I use to be sure and confident they are spoofing me somehow but do not have any of this control they claim to have.

On the internet last night I saw references to SPF and DKIM

I have my own basic hosting package with HostGator using  cpanel, is it one of these services I need to request from them, do I need to change some of my email settings / security or do I need to change something with 123-reg who hold my domains?

They have both offered me so many diferent things in recent months but not sure which one is required.
IT Pros Agree: AI and Machine Learning Key
IT Pros Agree: AI and Machine Learning Key

We’d all like to think our company’s data is well protected, but when you ask IT professionals they admit the data probably is not as safe as it could be.

Office 365 - Email Archive

Client has been using Office 365 since March 2012. At the time all onprem mailbox data was imported (using Migration Wiz).

Directors have requested that all email data prior to 1st September 2012 is now archived off of the system and held locally (external disk/s) which will be stored by one of the Directors.

I know about using Office 365's Online Archive systems (as per here) as well as retention policies. This is not what they require.

They want all email data prior to that date to not appear anywhere in the system.

Is this fesabile?

Hi Guy,

Live exchange 2016 server needs to be updated from CU2 to Cu8  and has been running without any issues  (4.7.1) Currently getting an error in a bmr'ed test environment when trying to go through the above update process - server is in maintenance mode but still noticed all exchange services running.  Also noticed none of the other (think there are 4) system mailboxes show up when searching in ECP but the accounts are disabled in AD. Exchange transition was from 2010 - 2016.

Any ideas about this, could I just remove the mailbox. Note: the guid is not showing up in Get-Mailbox -Arbitration

The following error was generated when "$error.Clear();
            $mailboxId = "SystemMailbox{D0E409A0-AF9B-4720-92FE-AAC869B0D201}";
            Write-ExchangeSetupLog -Info ("Retrieving users with LastName=$mailboxId.");
            $arbUser = @(Get-User -Filter {LastName -eq $mailboxId} -IgnoreDefaultScope -ResultSize 1);
            if ($arbUser.Length -eq 0)
                Write-ExchangeSetupLog -Info ("Retrieving arbitration users with LastName=$mailboxId.");
                $arbUser = @(Get-User -Arbitration -Filter {LastName -eq $mailboxId} -IgnoreDefaultScope -ResultSize 1);

            if ($arbUser.Length -eq 0)
                Write-ExchangeSetupLog -Info ("Installing user account with Name=$mailboxId and LastName=$mailboxId.");
                Install-UserAccount -Name $mailboxId -LastName …
hello guys

i'm looking for a way to circumvent the builtin postfix security that produces "mail for loops back to myself" which is a bit too trigger-happy for my situation.

if you know what triggers the message ( remote banner, ip addresses checked against the host's addresses or declared in some hidden location ... ) i'm also interested

note that i actually WANT the mail to loop (ONCE) and this is controlled : i'm purposely applying smtp: as a content-filter to mail handled by pickup. i have a policy daemon that needs to handle all outgoing email including mail dropped using the maildrop+pickup mechanism. pickup itself does not feature querying a policy dameon.

obviously a different way to hack pickup into interrogating the policy daemon would be welcome as well.

i already know of a few ways to circumvent but they are all bazookas : replacing the smtp: transport with a custom script or possibly deliver through pipe and a shell script would work but i'm expecting something much simpler.

thanks for your time


ps : anyone who just wants to explain how what i'm doing is bad/useless/evil without producing a way to hack pickup into interrogating the policy daemon. please refrain from posting. this is the feature i need.
Dear Experts, I could not delete the message in Exchange 2016 like before.

Here is the screenshot, yellow square is the user mailbox, blue square is the distribution mailbox. So what are the differences between DROP and SEND in Agent tab?

The second screenshot was the result after issued command to delete, it said success but the message was still in the recipient's mailbox

Can you please suggest? Many thanks!
I do not know why Thunderbird does repeatedly prompt below for password, while I'm using the domain account with correct password entered.
Getting a lot of undeliverable email notifications -

Reported error: 550 5.4.355 Remote server returned recipient domain does not exist -> 553 #5.1.8 Domain of sender address <xx@xxxx.org> does not exist
Last week I opened my Outlook email (pop3) and noted that I had around 1700 unread messages, I thought, oh boy they found me expecting to find a ton of spam, but no.

While much of it was spam, a great deal was email I wanted to get, and it all arrived that day but was sent as long as 6 months before.   This was from sites like zip-recruiter, dominos, Dell, and multiple other domains.

I have been receiving mail from all of those sites, these were messages that simply sat somewhere in limbo?  

I changed my email password.  But I have no clue as to why this happened, or if it is going to happen to others, where do I look for answers?  The server logs only indicate that they all arrived the day they did. It seems like they were being "held" somewhere.

technical notes:  I do have my account on my phone (IMAP - turned that off), using ALT-N Mail Daemon (not exchange), NO one else (132 users) has reported this issue or anything even similar.
This started yesterday around 8am that it was reported we couldn't send or receive any email.  Both inbound, outbound and internal email was no longer working.

I restarted the server a few times and exchange services and found that the Microsoft Exchange Transport service was stuck in a "Starting" state but would never start.  Through research I found some suggestions about renaming the que directory at C:\Program Files\Microsoft\Exchange Server\V14\TransportRoles\data\Queue and allowing exchange to re-create it.  

I found the mail.que file to be around 15gb if I remember correctly.  I was able to kill the process, rename the folder and exchange recreated it and mail started flowing again for awhile then stopped again.  This process was repeated several times as I continued to troubleshoot the issue.

Eventually, after almost 12 hours of suffering with this I ran this script:
Get-MailboxDatabase -Status | Select-Object Name,@{N="DatabaseSize GB";E={"$([math]::round($_.DatabaseSize.Tobytes() /1Gb, 2)) GB"}},AvailableNewMailboxSpace | Sort-Object Name | fl

The result was something similar to this:
Name                     : Mailbox Database ####
DatabaseSize GB          : 539.01 GB
AvailableNewMailboxSpace : 21 mb

Interestingly it's odd to me that the databasezize in GB is 540 (and doesn't seem to ever grow).  The drive exchange resides on has 383GB free space.

Anyway, I watched this for awhile and saw the availablenewmailboxspace continue to shrink and …
We've got a Linux server which has been running as a mail server (Sendmail) for years

DNS listings for SPF, DKIM, DMARC and ADSP has been in use for the past 3 months with no issues.

For DKIM we're using OpenDKIM and two days ago we've installed OpenDMARC and are still in the testing phase (We're not sending reports at this time)


For the life of me I can't figure out what I'm missing

I'm trying to figure out how to get Sendmail via OpenDMARC to follow an established policy of a received email by Rejecting or quarantining a email (as specified) if the message alignment fails .
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Protecting & Securing Your Critical Data

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i have outlook email with huge content. i like to search in that email say xyz
if i click control+F it is opening new reply email window.

what is the shortcut to search email content
not sure why there is no search button
please advise
Currently we are using AD on Windows server 2016 and Exchange Server 2016. We want to add Microsoft office online exchange 365 as a load balancer in DAG. It is possible?
The user received a legitimate email with a return address using their text mail address. However they didn't send the email, they only received it.  The sending address is their phone number @ mms.att.net
The user has an iPhone, an iPad and an iMac.  The email was received on the iPhone and iPad, but not on the iMac.  

Is there a way to see the header on an email received on an iPhone or iPad?

They have since called AT&T and made sure that they don't share their phone number account with anybody else.
ATT told them that they also share a satellite TV account with another person, but that this other person is the only control for the shared account.

The user changed their iCloud password, and confirmed that they have 2-factor authentication turned on.

My guess is that their phone number is embedded in the Mac Messages app on some computer somewhere, and that when a file was 'shared' the Messages app sent the file using a wrong phone number.

Naturally, they don't want people sending out email using their AT&T phone number

Any idea how this return address appeared?


email with text mail address
User can’t remember Gmail password BUT has the account working on a laptop

Eventually that laptop will die

Is it possible to add a forward all email to another address in the mean time to be covered for that eventuality ?

* totally impossible to retrieve password - we have tried everything !

Forward possible to a new gmail account and we will store password this time - it’s  possible ? Without knowing password ?

Thanks !
1.pngso all of a sudden some emails stop flowing and my connector is not validating, been setup for years and we did not change any server or network settings

i have Office 365 and a hybrid server - exchange 2010

the emails that are failing are coming from my mercury server and flows thru my exchange to office 365. i have contacted microsoft support but they are saying its an internal issue.
Hi guys,

I got a pop3 email in mac outlook. I want to transfer all emails to a office365 outlook profile in my Mac computer. I recently migrated from pop3 to office365. So doing this transfer to have my old emails in office365.

So in outlook, I got both profiles now. Old pop3 email and office365 Email. I can drag and drop each folder email. But there are many sub folders in inbox, which will
Be difficult to crate all folders in new office365 inbox and then doing drag and drop each folder.

Is there any other way to do it in a better way.
Guys I am having a significant problem I recently change my email password in Gmail know I forgot the password and the recovery email account I don’t have access. How can I recover my account?
Hi Experts ,

I have 2 Exchange servers , both running Exchange 2013 in the same domain.
1st Server is Srv3 which was the first Server setup and running Exchange 2013, the 2nd Server is Srv6 this is the 2nd Server running Exchange 2013.
I want to decommission Srv3 and make Srv6 my main and only exchange server.
I have moved my mailboxes across to Srv6 and have purchased a comodo payed cert and this is also installed on Srv6.
Srv3 has a self signed cert installed.
I am looking for some help on decommissioning Srv3 and making Srv6 my primary and only exchange Server.
if I turn off Srv3. I can access my Mailboxes and I can sent mail as now going trough Srv6, but can't receive mail or get to my e-mail remotely (owa).
if I try and setup the receive connector on Srv6 to be the same as Srv3 but  it won't let me.
Any help or advise would be greatly appreciated
Thank you.
In a Nation Builder nation, I have a 700-member e-mail recipient list. The majority of these recipients were imported when my nation was set up a couple of months ago. Email to these recipients is solicited because they all pay a monthly/annual fee for membership.

I've sent about a dozen email blast in this time without problem, and I get stats on how many people opened links inside the emails, how many bounces, how many are ad addresses. However a couple of weeks ago, I sent one out and it first reported everything to be OK, with zero bounced, but after about 4 days, the bounced shot up to 117. This was highly irregular because the highest number of bounces before this was about 8. I had a look at the 117 and they are all Yahoo, AOL or Sky addresses, and since AOL and Sky go through Yahoo, we can assume that this is specifically a Yahoo problem. Here's the message that appears in Nation Builder next to each bounce...

4.0.0 Email was deferred due to the following reason(s): [IPs were throttled by recipient server]

I've done two more blasts since this, and the same thing happens. I've checked with a few owners of these email addresses and can confirm that the emails are not being received.

Is there anything I can do to help this situation, either on Nation Builder, on Google G-Suite, or on Yahoo? I've contacted Nation Builder support, but all they suggested was that I send a handful of emails at a time in order to rewarm Yahoo. But this could take a long time, …
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i finished installing the exchange 2013 CU 21 and unable to launch the ecp or OWA, if anyone can please help it would be great.

Error Message :- Outlook
Bad Request :(
The request sent by your browser was not valid.

I have set up a new BigCommerce store, which is live and operating fine. However, I am having trouble setting up the third party email on the clients domain name and email hosting.

Mail can be sent from the domains webmail but can't be received. I am getting this message when sending to:

all relevant MX records point to non-existent hosts

Any help would be appreciated.
I can't seem to get any exchange mail on my iphone X.  We're running on premises Exchange 2010.  When I add the account on my iphone, I choose exchange and enter in all the details.  It passes, I get all "checkmarks", but no mail will load.  Folders won't even load.   Any ideas?  Btw, this very phone had email working just yesterday, but I decided to reset to factory and start from scratch.
Configure Exchange 2013  autodiscover and Web Services

I would like to know if I will have to configure Autodiscover  URL on each CAS server or just one of the CAS servers.
I also want to know if other Web services URLS such  ECP,OWA,OAB,ACTIVESYNC,OutlookAnyWhere,etc.... will have to be configured on each CAS Server

Thank you.
Hosting company has a button tie enable IMAP

Should it make any difference if it’s on or off ?

User id currently using pop

Recently upgraded Exchange from 2013 to 2016. Everything looks good and have been running for over a month without issues. Currently 2013 is in co-existence as its also the file-server role and although I've dismounted the EDB from old 2013 server, I havent uninstalled Exchange from it.

I wanted to do some delivery reports under Mailflow, and got this error - Value specified for a parameter of type Microsoft.Exchange.Diagnostics.MessageTrackingEvent is invalid: SENDEXTERNAL.

Any ideas?

Any help is appreciated, thanks!

Email Servers





Within Internet message handling services (MHS), a message transfer agent or mail transfer agent (MTA) or mail relay is software that transfers electronic mail messages from one computer to another using a client–server application architecture. A MTA implements both the client (sending) and server (receiving) portions of the Simple Mail Transfer Protocol (SMTP). The terms mail server, mail exchanger, and MX host may also refer to a computer performing the MTA function. The Domain Name System (DNS) associates a mail server to a domain with mail exchanger (MX) resource records containing the domain name of a host providing MTA services.