Send mail to exchange online using standard smtp session part 2#4

of 22 | Send mail to Exchange Online using standard SMTP session | Part 2#4
Written by Eyal Doron | o365info.com | Copyright © 2012-2015
Send mail to Exchange Online using
standard SMTP session | Part 2#4
In the current article, we will review the process in which we want to enable a mail
client such as Printer or application to send an E-mail message via the Exchange
Online server. As mentioned in the former article – Send mail to Exchange Online |
Part 1#4, we can address the Office 365 mail services using one of the following
options:
 Option 1 – creating a secure communication link between the mail client and
the EOP server who is based on the mandatory requirement for encryption
and authentication by the mail client.
 Option 2 – creating a “non-secure” communication link between the mail
client and the EOP server in which the mail client is not required to provide
user credentials (anonymous) and the connection is based on the SMTP
protocol (non-encrypted communication link).
The option that we will review in the current article is – “option 2″.

In the next article (SMTP Relay in Office 365 environment | Part 3#4), we will review
“option 1” – using a secure communication link to EOP using SMTP mail relay.
Send mail to Exchange Online – Article Series
 Send mail to Exchange Online | Part 1#4
 Send mail to Exchange Online using standard SMTP session | Part 2#4
 SMTP Relay in Office 365 environment | Part 3#4
 SMTP Relay in Office 365 environment | Troubleshooting scenarios |Part 4#4
When we want to use the option of – non-secure” communication link to Exchange
Online mail server, the process is quite simple.
The main tasks that we have are:
1. Get the host name of the Exchange Online server (EOP) that represents our
public domain name.
2. Configure the mail client to connect the Exchange Online server using the host
name
3. Create connection filter rule or Exchange Online rule (transport rule) that will
prevent the scenario in which Exchange Online will identify the E-mail as spam
mail.
Get the host name of the Exchange Online server who
represents our domain in Office 365.

There are a two ways that we can use to get information about the FQDN (Fully
Qualified Domain Name) of the Exchange Online that “send E-mail for our domain”
Option 1: Office 365 administrate portal.
 Login on to Office 365 portal as global administrator
 On the left sidebar – choose the domain
 Choose – Manage DNS
Under the Exchange Online section, look for information about the MX record
hostname (POINTS TO ADDRESS). In our scenario, the Exchange Online server who
will “represent” our organization is: o365info-com.mail.protection.outlook.com
Option 2: using the nslookup tool.
Another option for getting information about the “Host name” of the Exchange
Online mail server that “represent” our organization is: by using the nslookup tool.
 Open the command prompt
 Type the command: Nslookup

 Type the command: set type=mx
 Type the name of the domain that you want to display his MX record. In our
scenario: com
In the following screenshot, we can see the result of our MX query.
In our example, the host name of the Exchange Online server who represents our
domain is: o365info-com.mail.protection.outlook.com
Recap – enabling mail client to send E-mail message via the EOP
To enable a specific mail client to send an E-mail message via the EOP, all we need
to do is configure the host name of the EOP server as the “mail server”.
In our specific scenario, the Hostname who represents the domain
name: o365info.com is: o365info-com.mail.protection.outlook.com
Verifying communication with Exchange Online using
Telnet
In case that you want to check or simulate the communication channel to the EOP
server using a “standard SMTP session”, you can try to send E-mail via EOP using
Telnet session.

In the following section, we will demonstrate how to use Telnet client for verifying
the communication channel with EOP.
Note – the Telnet client is not installed by default in the windows OS, you will need
to install the Telnet client.
 Windows 2008 – use the Server manager ==> add feature option and, then add
Telnet client.
 Window 7,8 – control panel ==> Programs and features ==> Turn Windows
features on or off and then, add Telnet client.
 Another option is to run the following command from the command
prompt: pkgmgr /iu:”TelnetClient”
In our example, the host name of the EOP that represents the domain
name: o365info.com is: o365info-com.mail.protection.outlook.com
Open a new command prompt and type the Telnet command using the following
syntax:
Telnet <Host name> <port>
In our example: Telnet o365info-com.mail.protection.outlook.com 25
In the following screenshot, we can see the result, the answer from the EOP server
appears on the screen:

220 AM1FFO11FD029.mail.protection.outlook.com Microsoft ESMTP MAIL Service
ready at Sun, 3 May 2015 08:26:10 +0000
At this stage, we can know that
1. We know to “right host name” of the EOP server that represented our domain.
2. That the EOP server name was successfully resolved to an IP address.
3. That we can create an SMTP session (the firewall enables us to use SMTP, etc.).
In our scenario, we will send an E-mail message to a recipient
named: john@o365info.com
To simplify the test process, we will use the E-mail address of John also as the
“source E-mail address”.
In simple words: we will simulate a process in which John sends E-mail to himself by
addressing the EOP server.
1. Starting an SMTP session
The first command that we use for starting the SMTP session with the EOP server is:
Helo
The result is an answer that sends from the EOP server:
250 AM1FFO11FD029.mail.protection.outlook.com Hello [212.25.80.236]
2. Define the source recipient
In our scenario, the source recipient is: john@o365info.com
The Telnet commands that we use for configuring the source recipient is:
mail from:john@o365info.com
The EOP server reply is:
250 2.1.0 Sender OK
3. Define the destination recipient
In our scenario, the destination recipient is also: john@o365info.com
The Telnet command that we use for configuring the destination recipient is:

rcpt to:john@o365info.com
250 2.1.5 Recipient OK
4. Create the E-mail message content
To be able to “tell” the destination mail server that we want to enter the E-mail
message content, we use the command: data
354 Start mail input; end with <CRLF>.<CRLF>
5. Ending the SMTP session
To be able to “tell” EOP server that we want to end the session and send the E-mail
message, we use the period charter: .
In our example, we see the response of the EOP server. The message “Queued mail
for delivery” is usually a good sign.
The meaning is that the destination mail server agrees to accept our E-mail
message and, the E-mail message was placed on the mail server queue.
250 2.6.0 <f9b0d90a-b4b6-4d72-9a7d-
0a5c92b71960@AM1FFO11FD029.protection.gbl>
[InternalId=13370233193878,
Hostname=HE1PR05MB1146.eurprd05.prod.outlook.com] Queued mail for delivery

Verifying the SMTP communication channel with Exchange Online
Another way that we can use for: Verifying the SMTP communication channel with
Exchange Online and for getting more detailed information in a communication
failure scenario is a very nice and useful tool named: Basic SMTP Telnet Client
Note – the Basic SMTP Telnet Client doesn’t include an installation file but instead,
just a simple EXE file named: telnet25.exe
All you need to do is just double-click on the EXE file.
In the following section, we will demonstrate how to use the Basic SMTP Telnet
Client tool for creating an SMTP session with the Exchange Online server.
Scenario description: in our example, we will address the Exchange Online server
who represents the o365info.com domain name, and we will send the email
message from:john@o365info.com to himself.
1. Receive Connector IP – in our example, we will use the Exchange Online server
hostname: o365info-com.mail.protection.outlook.com
2. TCP Port – type 25 as the port number
3. Mail form: The E-mail address of the “source recipient” (in our
scenario john@o365info.com)
4. Recipient to: The E-mail address of the “destination recipient” (in our
scenariojohn@o365info.com)

5. Subject: any text that you would like
To be able to send the E-mail message we need to move on to the “Telnet” tab
 Click on the SEND button.

In the following screenshot, we can see the log of the SMTP session.
We can see information about the source and the destination recipients.
We can assume that the mail delivery completed successfully because in the Log we
can see the information: “Queued mail for delivery”.

Prevent the scenario in which E-mail is identified as
spam.
When we implement the configuration of “anonymous” access to the EOP, meaning
is addressing the MX record of the EOP server who represents our domain name at
Office 365, one of the disadvantages is that most of the time, the E-mail message
that will be sent by the mail client (device or application) will be identified by the
EOP server as spam mail.
The reason is that when we use the address the EOP server and identify ourselves
as a recipient who use the same domain name is the domain name that is
“attached” to the EOP server.
For example: in a scenario in which the EOP server represents the domain name,
and we configure our mail client to use the E-mail address: printer@o365info.com,
when we address the EOP server, the fact that our mail client is not authenticated
the EOP server recognizes the source recipient as an element that tries to spoof his
identity.

For this reason, the EOP server will not delete or reject the E-mail message, but
instead, “stamp” the E-mail message with a high value of SCL (Spam Confidence
Level).
The E-mail message that will be sent to the Office 365 recipients will be saved in the
junk mail folder.
In the following screenshot, we can see an example to a scenario in which mail that
was sent by a mail client to EOP using the MX record hostname, reach the
destination recipient mailbox but the E-mail message was “stamped” as a spam
mail.
When looking at the E-mail header, we can see that the EOP defines the SCL value
as “9”.
The meaning is a very high value which “tell” to the destination mail client to relate
to the specific E-mail message as a “dangerous mail”.

Creating Exchange Online Bypass spam rule
To be able to deal with a scenario in which EOP server will “stamp” E-mail messages
that sent by a mail client as a spam mail, we can create a special Exchange Online
rule defines as:
bypass spam rule.
The logic of the Exchange Online rule is implemented as follows -condition and
action.
The condition: if a mail sends from a specific recipient or from a specific IP address.

The action: relate to the E-mail message as trusted. In other words – set the SCL
value of the E-mail message to -1.
The value of “-1“, “tell” to the mail client that the E-mail message is trusted by the
mail server.
In the following section, we will demonstrate how to create an Exchange Online rule
that will apply the bypass spam rule for each mail that sent from a recipient who
uses the E-mail address: printer@o365info.com
 Login to the Exchange Online management portal
 Choose the mail flow menu and on the upper menu bar choose roles.
 Click on the plus icon for creating a new rule
 Choose the option: Create a new rule…
 In the name box, type the rule name. In our example –accept mail from on-
Premises printer
 Choose the option box – *apply this rule if…
 Choose the option: The sender is….

 In the check name box add the name of the source recipient. In our example the
source recipient is – print@o365info.com

In the next step, we need to define the “action part” of the rule.
Theoretically, to be able to configure the condition we need to “move on” to the
“*do the following…” but when choosing this option, we will not be able to find the
option of creating a bypass spam rule.
To configure the required condition, choose the option: More options…

 Choose the menu – Modify the message properties
 Choose the menu – Set the spam confidence level (SCL)

 Choose the option – Bypass spam filtering

 Choose the option – Save

In the following screenshot, we can see an E-mail message that was sent to the
Office 365 recipients from the source mail client (the printer device in our scenario).

In the following screenshot, we can see that when looking at the E-mail message
header that was sent to the Office 365 recipient, the SCL value is: “-1”

Send mail to exchange online using standard smtp session part 2#4

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Send mail to exchange online using standard smtp session part 2#4