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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I have a client that deleted all of his deleted emails & swears that took alot of his inbox & folders...

I do have a backup of all his emails, but when I replace the .ost as soon as it goes it syncs with GMAIL it re-deletes all of his emails to its current state.

Is there a way to make the OLD .ost be the correct & the GMAIL sync to that ?  I could not find where it was talking about unchecking "cached email"

He is using Outlook & I want to use his OLD .ost to be the correct email & then update from there.

Any direction would be great.  Thank you.
I get file "courier-imap-5.0.8.tar" (attached) but am not sure about its setup in Ubuntu. Please help.
SMTP how to programmatically set the priority in an email
where specifically would there be clues in a Office365 mailbox or logs associated with Office365 if any mail which has hit the mailbox contained malware? And what actual impact that malware has had, e.g. forwarded sensitive information from the mailbox outside.

Is it common/plausible that malware via email could then leak other emails from the account out to another address etc.
I am Unable to send most emails to most domains. We are using Sophos XG as the sending relay.
All (almost all) emails are stuck in the queue with error:
421 service not available (connection refused, generic failure).
some emails that give these errors sometimes are getting delivered.
Problem started only yesterday!
I am trying to set a Microsoft Live account in my Outlook 2010 but keep getting error.

I have my Desktop Outlook 2010 setup as the following:
In Outgoing Server >> enable: My outgoing server (SMTP) requires authentication
In Advanced >> Incoming server (POP3): 995 >> Use the following type of encrypted connection: TLS
Outgoing server (SMTP): 587 >> Use the following type of encrypted connection: STARTTLS

What I did notice that in Advance "Use the following type of encrypted connection:" says to use STARTTLS, but my Outlook only have 4 options: None, SSL, TLS,  Auto - I have tried all 3, no success.

Please let me know what steps to follow to setup a Microsoft Live account  in my Outlook 2010.
We have a situation where our IPS and sometimes our SPAM filter blocks specific IP addresses that are sending mail from GMail and Google mail. In every instance these blocked IP's are on an Internet black list. Googles' solution is to white list these servers and any other Google servers (literally thousands of them), this is insane to me. I am sure others have encountered this situation and I am wondering how do you handle it.
I am using Outlook 365 on a computer running Windows 10 Professional 64 bit.   When I try to set up my POP email I cannot get the right settings for outgoing server.   On other computers I can specify that the outgoing sever requires authentication.   Can I set up my email in Outlook any other way than POP?
Is use DMARC and SPF to protect my domain, however a client recently became infected with malware and propogated the malware via spoofed email.  Now clients of mine are receiving mail addressed as me.  The question is how, what have I missed here.

DMARC Record
v=DMARC1; p=none; rua=mailto:helpdesk@mydomain,;,; fo=1

v=spf1 +a +mx +ip4:M111.111.111.111 ~all
  • IP is my public IP address
  • MX is my cload spam filter provider.
We have dmarc implemented and I usually collect and review the reports weekly. About 3 weeks ago, the number of threat reports massively jumped and remains alarmingly high. Looking at a 2 month period: October-November, 7k emails passed dmarc, 70k have been reported as threats. This all looks like someone external has tried to use my domain and is failing the spf and dkim checks and I am getting the reports about it. I expect dmarc is working as it should but the volume of emails and the sudden increase around 3 weeks ago is what has got be concerned. Unfortunately I have had no reports from humans in that time of fake email coming from my domain. I do not even know the content of the emails or the recipients. All I know from dmarc is that they exist. My dmarc policy is set to quarantine rather than reject so conceivably people are still seeing the emails. I would appreciate any advice from the email experts here.
Dear Experts

As per the policy we must deploy on-premise email server and we are planning to go for exchange enterprise or standard.  However our user base is 20 users at present and we may maximum have 25 to 30 users in next 5 years. We are planning for barracuda email security appliance.  
1. Please suggest is it recommend going with exchange standard OR exchange enterprise
2. As security point of view we should have tight security hence will there be any difference between standard and exchange
3. Understood standard will provide 5 mail database will this be sufficient for 25 to 30 users
4. What all features that will not be available in exchange standard compared to exchange enterprise.
please help, thanks in advance
My email issues are continuing, but only with domains hosted by Yahoo. My Spf record is correct and I have fixed my ptr record today as well (Finally in place around noon). Here are my DNS Records and a screen shot of the issue. This issue is only occurring with email addresses or domains hosted by Yahoo. Everything else works as expected.
A client of our's email isn't working via outlook. I thought perhaps the pst was bad, but it is failing on all computers with outlook. I tested on their system to the web version and it signed in fine. I went back and deleted the mail account on their computer and set it up as active sync and it works fine from outlook. However, if I try to add their email as an IMAP as it is created on the mail server, it fails.

I adjusted the IP from 143 to also try 993. Also attempted with the firewall disabled. It was working fine for a while up to today. The error is uploaded.
I would like a script that I can modify to be able to the following:

Use Office365 smtp
Port 587
to accept username and password
have a pdf attachment to it called 1.pdf
Send to a distribution list from. EmailList.txt
msg-header.PNGmail delay

one of the user complain receive one email from one of the recipient facing mail delay issue ,i using mx tools box and found that is one hours delay from recipeint server to our server  ,please advice what should i do ?
I logged into my gmail account with my correct email address.
I typed my correct email password!
I got the "doesn't recognize this device message" message.
Gmail wanted to verify my account using a phone number which I don't have any more.
I clicked to "send verification code to my email account".
I received the email verification code and correctly entered it.
Gmail said "Thank you for confirming" BUT STILL DIDN'T LET ME INTO MY ACCOUNT!
(See graphic).
HELP.  How do I get into my account. Is there a help desk? or help email or help "chatline" I can  go to.

I am trying to send rather important emails to a person in the USA that has a Cox network address. They are all bouncing back to me with the message: This is the mail system at host

I'm sorry to have to inform you that your message could not be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can delete your own text from the attached returned message.

                   The mail system

<the guy I am trying to email address>: host[an ip address] said: an ip address
    <my email address> server temporarily unavailable. Refer to Error Codes
    section at
    for more information. AUP#CXMXRT (in reply to MAIL FROM command)

Is this a problem with MY email provider or Cox? How do I solve this the easiest way possible?
Using my gmail account to send an email, is it possible for the recipient to know which country I sent the email from if I was travelling?  The same question applies to any any provider other than gmail.
I have an email account. It has the form:
In order to login to the email I have to browse to the website and, in order to log in to my email I have to enter the following details:
password: password1 [This was a password of my choosing]
Despite the fact that I provide authentication details on the website, once I am authenticated, I am diverted to a Gmail account with the company logo in the top right corner.

I would now like to transfer all of the emails from this (Gmail) account to another new, personal Gmail account. In order to do that I have been into the settings of my new Gmail account and used the "Import mail and contacts" process. The authentication details that I then provided in order to fetch the mail from the pop server were:
password: password2 [This is a random-looking password provided to me by the company]
pop server:

I successfully managed to set the "Import mail and contacts" process going. Unfortunately, it only transferred two thirds of the emails. Gmail did not provide any error message. It took me a while to work out that the company Gmail has a 30GB limit whereas the new personal Gmail has a 15GB limit and when it reached 16.5GB, the import stopped.

I purchased the 100GB package. Once this was in place, the import did not start up again. When i tried to start it off again, I just ended …

I'm looking for a SMTP test tool which:

- Can use TLS connection
- port 587.
- can add username /pw

Any idea where I get a that tool?
Dear Experts

I am hoping someone can assist me with the following issue. I have SPF and DKIM configured on my domain, which appear to be setup correctly but when I examine the message header of an email I sent I see the following entry "None ( does not designate permitted sender hosts)"

Just to add I am using Exclaimer for signature management.

Please can someone examine the header below and advised if I configured something incorrectly.

Received: by 2002:a4f:c15:0:0:0:0:0 with SMTP id 21csp930979ivm;
        Wed, 21 Aug 2019 06:30:56 -0700 (PDT)
X-Google-Smtp-Source: APXvYqyk6Zvuz4Zzp1WUwoJQlz3EsF/mENO5B7uNOXkWXKiQUJ9CmIl25//eS3gDvDa/NqaFIZJg
X-Received: by 2002:a17:906:158c:: with SMTP id k12mr31626198ejd.83.1566394255976;
        Wed, 21 Aug 2019 06:30:55 -0700 (PDT)
ARC-Seal: i=2; a=rsa-sha256; t=1566394255; cv=pass;; s=arc-20160816;
ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed;; s=arc-20160816;
Hi Experts,

I have a some problem to understand some things on Exchange 2016.

First of all, I want to explain how works my exchange :

  1. DAG - 3 members
  2. 1 Edge on the DMZ :
  3. 1 Fortigate to do the link between the Public IP and the EDGE on the DMZ : Client -> Public IP  -> EDGE Server
  4. Here the smtp :
  5. I have an external Client who send mail through our Exchange :

Then, I have a receive connector on the Edge :
AuthMechanism                             : Tls, ExchangeServer
Banner                                    :
BinaryMimeEnabled                         : True
Bindings                                  : {}
ChunkingEnabled                           : True
DefaultDomain                             :
DeliveryStatusNotificationEnabled         : True
EightBitMimeEnabled                       : True
SmtpUtf8Enabled                           : True
BareLinefeedRejectionEnabled              : False
DomainSecureEnabled                       : False
EnhancedStatusCodesEnabled                : True
LongAddressesEnabled                      : False
OrarEnabled                               : False
SuppressXAnonymousTls                     : False
ProxyEnabled                              : False
AdvertiseClientSettings                   : False
Fqdn                                      : SRV-DAG-EDGE.contoso.local

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How can I send a text from my computer to a mobile phone number if I do not know the name of the carrier?
I have an existing Outlook 2013 setup with one POP3 email configuration. I purchased a new POP3 email account that I wanted to add to the existing Outlook Profile, set as default, and remove the  original. I believe I made a mistake deleting the original POP 3 account  from my registra before removing it cleanly from Outlook.  So, when I went to open the account settings within Outlook, it won't open. I am unable to access the account to delete it from the OUtlook Profile. Luckily I was able to switch the default to the new POP 3 account so Outlook does open, yet I believe I will have problems with  the  calendar, tasks, etc. I already know I am  unable to reply from the new account.

How can I get rid of the original email account, and have all the Outlook functions (Calendar, Tasks, Contacts, etc.  associate to the new user?

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.