I often have a situation where I need to setup some kind of email notification for some third party app and it often doesn`t work. In order to validate email communication telnet is my best bet.
If you are testing from Windows Server 2012 R2 (like in this case) you`ll first have to enable Telnet Client. That can be done by going to Server Manager | Manage (top right part of the screen) choose Add Roles and Features from Manage menu | click Next until Features menu | choose Telnet Client | Install
Open Command Prompt with Administrator privileges
Screenshots are here just for comparison of command outputs, many vital parts of information are blacked out for security purpose, because I`m testing on actual domain.
Into cmd enter following commands (mail.domain.com change with actual domain you want to test) :
telnet mail.domain.com 25
You`ll get something like this:
You should get following response. If ok last line should be 250 OK, or something similar like in screenshot
Result should be 250 Sender OK
Result should be 250 Recipient OK
Into next line enter:
You should get status 354 Start mail input
Subject: test subject
(I entered testna poruka, you can write anything you want instead of test subject)
Press ENTER two times and in second line type period (.) and confirm with ENTER again.
This is the result I received after pressing enter after entering period(.)
Shortly after confirming send I received email
My test was successful. If you have any problems refer to Technet – https://technet.microsoft.com/en-us/library/aa995718%28v=exchg.65%29.aspx
To exit session type: