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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'm trying to find more info on the SPF record for spf.salesforce.com.  It is in a format I'm not familiar with:

PS C:\Users\jason.crawford> Resolve-DnsName -Name _spf.salesforce.com -Server -Type txt

Name                                     Type   TTL   Section    Strings
----                                     ----   ---   -------    -------
_spf.salesforce.com                      TXT    2982  Answer     {v=spf1
                                                                 exists:%{i}._spf.mta.salesforce.com -all}

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Hi, I use Zimbra Collaboration Suite (8.8.7 version, open source edition).
I manage one domain with about 50 mailboxes.
I need to "purge" messages on some mailbox (eg. delete messages older than last year).
I cannot use global retention policy, because I need to take action only on few users.
How can I do this?
Thank you!
I am setting up a new HREL 7 server and trying to configure Postfix to send from one of the virtual IPs assigned to the server. I can successfully send mail, but the problem is that when mail is received, the header shows the server's primary IP instead of the virtual IP. It is flagged as spam due to a possibly forged header. The header includes:
Received: from mail.mydomain.com.com (unknown []

What am I missing?

Assumptions (not actual names/IPs):
Server's primary IP:
Server virtual IP = (mail.mydomain.com.com)

DNS records:
mail.abc.com  A
mail.abc.com  TXT   v=spf1 ip4: ~all

/etc/hosts: mail.abc.com

Postfix Configuration: (/etc/postfix/main.cf)
myhostname = mail.mydomain.com.com
mydomain = mydomain.com.com
mynetworks =
inet_protocols = ipv4
inet_interfaces = $myhostname, localhost

Refer to above link: it's said Barracuda has a list of bad IP : how can we download it?
I would also like to download for SpamHaus & CBL & any other if possible?
I am running MS Exchange 2013 CAS/MDB and an Edge Server in my environment. When I set up the Edge Server I had to run a power-shell command to promote it and join it to the Exchange Server. I am now thinking of going with a different solution for my spam filter such as Proxmox Email Server or Mailcleaner. My question is, do I need to do anything specific to demote the Edge Server? Or can I just install the new appliance and point my firewall to the new mail gateway?

Thanks in Advance.
I have critical situation , suddenly any user cant receive mails in my organization , i have exchange 2007 i can send mails but nithing reicved even internal
what i can do
i review all settings which was used before and it is up and running
Dear Experts

We are using offfice 365 SMTP relay to send mails to the external users through the CRM application, i,e option 3 on the following URL
https://support.office.com/en-us/article/how-to-set-up-a-multifunction-device-or-application-to-send-email-using-office-365-69f58e99-c550-4274-ad18-c805d654b4c4 , this CRM system is allowed only to talk with <domain>.mail.protection.outlook.com on port 25 and 587 and rest of the access to the internet is blocked, not access for this CRM system to http/https to the external network.
1. we observed the CRM system workflow triggers the emails to the external network users only when the port 80 is opened for the CRM system at the gateway/firewall level,  we noticed the CRM system gets connected to internet and connects to crl.globalsign.com  and from here it is connecting to office365 smtp and emails are delivered.
2. when we disable access to external network i,e port 80 http blocked for CRM system at gateway/firewall then emails does not flow no packets flow found hence no mails are sent.
3. When only allowed CRM system can talk to crl.globalsign.com  then emails are getting triggered.
can you please help me understand how this office365 is working when it is configured to the CRM system. is it essential that CRM system to be allowed to talk to crl.globalsign.com . please suggest.
Is there a way of blocking a delivery receipt from being sent to the sender of an email.  There is when there is a read receipt but how about a delivery receipt
hi guys

We've had an email that looks like it has come from a bank claiming that one of their customers have had a fraudulent transaction on their card from one of our stores. I'm almost certain it is a phishing email of some sort.

I wanted to verify with you guys whether it is likely that the email address has been spoofed.

I won't be able paste the email address it is coming from. But as it claims to be from a bank, the sending server was the following:

Connection  Accepted
Sending Server (mail-eopbgr100089.outbound.protection.outlook.com)
Sending Server HELO
Connection Started
28 Sep 2018 5:45:45 PM GMT+01
Connection Finished
28 Sep 2018 5:45:45 PM GMT+01

Am I right to assume that any 'Bank' that is using Outlook as its sending server is using spoofing tactics?

If we don't subscribe to among the lowest-end  O356 Exchange Online,
how can we further secure our email defenses (if we don't purchase
filtering tools like IronPort & Proofpoint)?

I've heard in Postfix forum that they link Postfix server to SpamHaus,
CBL (pls suggest more free Site Reputation services for emails):    can
 Exchange Online implement this?  Can we integrate with Virustotal?

Based on threat intels we get, can we add the hashes into our NIDS
CHeckpoint (assuming email payloads pass through it or in practice
people don't do this?) or Exchange Online??

Will hardening our Outlook client, MS Office, Pdf reader (& all the
'Mobile Codes' softwares) help?
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I am about to build a separate, stand alone CentOS 7 server to just run postfix.  I work for a fairly large company that has 3 email domains, for ease lets call them 1.com, 2.com and 3.com.

1.com and 2.com will be having that email redirected to mimecast (www.mimecast.com), however 3.com needs to have the email sent to a different location (an internal Exchange server).  The reason for this is that 3.com will, in a few months be moving to Office365.

My question is, whats the best way in postfix to say "if 1.com or 2.com send ->  relay it via mimecast, and for 3.com send it another destination.

I have worked with postfix quite a bit, however mainly using basic configs, or basic mail relay for one single domain.

Thanks for your time,
Currently using O365 and wanted to know if there are any commands that could list all mailboxes that utilizes a Safe Senders List as well as to list the contents of their Safe Senders List.
Email receiving issue on exchange 2013.
I have been facing issue with receiving email internally and from outside also.

There is error on queue management the remote pipeline has been stopped. it was running the command ......
hmailserver_log.txtI've been sending logs and reports from 3 sites at the rate of 20 per site per day.  It has always worked flawlessly - for years.
Suddenly, the emails don't get through from any of the 3 sites.
This happened for a few days about a year ago and then it fixed itself.  So, I didn't get any insight from that.

Here is the path:
Device or program sends an email. addressed to an outside address, via SMTP / local workstation LAN address where hmailserver is running (as a relay only).
hmailserver forwards the emails to fred@r........k.com at our external ISP mail system.
The ISP mail systems forwards the mail to the addressee at a domain / mail server that I "own".
The domain mail server delivers the mail to a POP account on one of my external workstations.
Like this
email to xyz@abc.com sent to server at [local IP addess]
hmailserver running at [local IP address] forwards mail via me@isp.com.
ISP send mail to xyz@abc.com
I get POP mailfor xyz@abc.com in my office.

I have attached a log from the hmailserver which you my well be able to interpret better than I.

In order to fix the disruption, it would be good to know where it's faiing…..
My client IPs has blacklisted only at Sorbs
Sorbs website – „Site Down for Maintainance“
Im waiting for Sorbs website to find out reason and to delist IP but in the meantime what can I do to find source of the problem.
Any advice?
Maybe it is false positive?
Hi Guys

I am needing to trash the contents of a 60+ Gig mailbox on our exchange 2010 environment.
I was looking at the below script and tested it on another mailbox and it works like a charm.

Search-Mailbox -Identity "Peter Pan" -DeleteContent

But as always the scope gets changed on min 99 and now the request is to delete all mail except 1 months (Latest mail) worth of mail in the mailbox.
Now I am not a guru on PowerShell, but surely there should be something I can add to my current command that will leave 1 months worth of latest mail and trash the rest?
Any  assistance win this would be appreciated.

From security reporting & analysis, I'll need to access our
Exchange Online (think it's ver 2016) to view

a) Spam, phishing, blocked emails
b) the blocking policies (whitelisting, greylisting, blacklisting) in place
c) DKIM, SPF, DMARC settings

I'm completely newbie to MS Exchange: can let me know screen by
screen (or step by step) where to view this after being granted
access to Exchange Online?

We did not get 3rd party email filtering tools (like Proofpoint),
just purely what's offered by O365
Single exchange server.
5 e-mail domains
Two mx records
One spf record in one „primary“ domain public dns.
Spf v=spf1 mx –all

What about other 4 domains

I think that someone trying to spoof this 4 domains e-mail addresses and sends spam.
Do I need to add spf record to other 4 domains and how to configure spf for other 4 domains.
Just enquiry,

I migrated  1 mailbox database from old to new server,

now the old exchange server have 1 empty user mailbox database (not using anymore)

I know it could not release disk space for server unless run offline defrag to the specify mailbox database.

Just need to ensure, if I remove mailbox database from ECP successfully, it will release the disk space for me?

and after removed the mailbox database, the EDB log file (such as E00002EBE90.log, per log 1 mb) is it safe to delete?

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I have a user using a web hosting company and their webmail to keep emails on the server and in separate folders.

We're moving him to a different hosting company. we want to move the emails / folders from that server to the new server.

I thought I was cute  - I connected outlook via imap to the old server, waited for it to stop saying sync'ing folders.
the exported as PST.

Changed the mail server  settings and pointed to the new mail server via imap.  Folders were empty and not many of them (in, sent, deleted, drafts).

Then I imported the PST into that account. Outlook shows all the folders, but they arent in the new webmail.

The folders / files in them show in outlook but not in the new server.

What's the right way to get emails on a pop / imap mail server into another server?
luxuryretreats.com and eag.com mail servers are hosted by "google apps". both companies are reporting that they're not receiving any emails coming from our domain rosenaviation.com. but we're receiving emails from them.

i did a test email and got these back
Delivery to these recipients or groups is complete, but no delivery notification was sent by the destination server:

i did a test and sent an email to any domain including gmail.com and all recipients received emails coming from rosenaviation.com
Dear Experts
We are having issue on CRM system not able to send mails through the configured SMTP server but the network team says the issue is from CRM application side however to come to the correct conclusion,
Used Telnet to test SMTP
1.On the CRM hosted Windows OS system did the telnet check with smtp host and port , it connects also performed following steps I,e setting smtp server , source domain, senders email and recipient email, message subject and body we are able to send and receive email
Please let me know the above steps does it passes through SMTP authentication OR not
2. configured email account in the CRM system with SMTP mail server.port: (SMTP server is smtp.office365.com)
check marked "use SMTP Authentication". provided user name and password  the result  is not able to send mail following popup from the CRM system
"Error Failed to connect to outbound SMTP Mail Server. The outbound mail server selected for the mail account you are using is invalid check the settings OR select different mail server" BUT when unchecked the "Use SMTP Authentication" that is disabled the SMTP Authentication then able to send mail out..
As mentioned above SL1 when able to send and receive email from telnet does it passed though the authentication , please help.
Hi I have worked in the capacity of  Microsoft Exchange server and AD for sometime, but recently have received additional duties and one of them is reading email headers. For example making a determination of why an email was blocked, tagged etc.. on firewall appliance. Any guidance on where I can receive resources to learn RFC's and how internet email work. I don't see a lot of material but only unix resources like postfix and sendmail. I I have been kind of winging it and using google but would like some more formal information about this stuff.
I set a new IMAP configuration through Outlook 2013 for one of my clients. He originally had a POP3 setup.

My client stated he was wasting allot of time updating his desktop Outlook after he made changes (read, delete, send, etc.) on his iphone, hence the move to IMAP.  

The transition was not easy! He had massive custom folders (including sub folders) under his inbox containing client emails over the years. He is basically keeping a history via his outlook. I ran into a ton of problems attempting to restore a PST backup to an OST IMAP account - too long to explain. At a certain point I was moving one folder at a time/counting emails. I finally got to the finish line. All the folders/emails were synced to the online email server.  As I'm about to report the great news, my client tells me he opened a suspicious word document which turned out to contain a virus.

So...I had to buy new drives , and perform a full restore of  recent backed up images. I bring the system back on line, it performs an outlook sync and proceeds to freeze up the on-line email server web account (purchased through a 3rd party vendor). I am now unable to access any folders, or emails either through the web interface (to a 3rd party email server) or through Outlook. I called up the 3rd party, who stated they will refresh their server. I await the results.

In hind sight, I feel like I should have kept those custom folders out of the sync process. At this point, it feels like a total mess.

I just successfully setup the Hybrid migration for office 365  on my exchange 2010 server on premise. i migrated two mail boxes to office 365, that was successful as well. i can route messages back and forth between the migrated accounts and the on-prem accounts. then i created a new account on office 365, when i try to communicate with that account from my on-prem emails i get a bounce-back error saying the account doesn't exist.  but i receive emails from  from the account. what could be the problem.

N.B: as per dns:
1. my mx records are pointing to the on prem server.
2: I have autodiscover pointing to my onprem as well.

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.