smtp send mail fail using postfix in Linux

nang 1 Reputation point
2020-12-19T04:33:47.437+00:00

I try to use postfix smtp service to send email in Linux.
but it return fail message**(Delivery has failed to these recipients or groups:)**

i follow this article to setup my postfix.
http://www.daliycode.com/info-3-201.html

I found my exchange server only support ntlm auth.

so I try to use telnet to auth and send email. but it alos fail.

telnet mail_server_domain 25
EHLO mail_server_domain
AUTH NTLM
base64_my_email
base64_password
535 5.7.3 Authentication unsuccessful

it return "535 5.7.3 Authentication unsuccessful" message.
so anybody know this issue?

Microsoft Office Online Server
Microsoft Office Online Server
Microsoft on-premises server product that runs Office Online. Previously known as Office Web Apps Server.
579 questions
Exchange Server Management
Exchange Server Management
Exchange Server: A family of Microsoft client/server messaging and collaboration software.Management: The act or process of organizing, handling, directing or controlling something.
7,326 questions
0 comments

2 answers

Sort by: Most helpful
Most helpful Newest Oldest
  1. Andy David - MVP 140.8K Reputation points MVP
    2020-12-19T12:43:21.133+00:00

    Why the need to authenticate to Exchange? Why not just send the message anonymously?

    0 comments
  2. Kael Yao-MSFT 37,486 Reputation points Microsoft Vendor
    2020-12-21T06:01:18.35+00:00

    @nang
    Hi,

    Agree with Andy,there is no need to authenticate.
    In your case, you may create a dedicated receive connector on your Exchange server and only allow your linux server to relay messages.
    You can find the detailed steps in this document: Allow anonymous relay on Exchange servers

    As long as you specific the ip addresses or ip address range that are allowed to use the receive connector, your Exchange server won't be used as a open relay.

    If the response is helpful, please click "Accept Answer" and upvote it.
    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.