MsExchange Blog Spot Telnet25

April 16, 2009

530 5.7.1 Client was not authenticated Exchange 2010

Filed under: Exchange 2010 — telnet25 @ 2:30 pm


After new installation you are able to sent mail out but not able to receive emails.The sending host is receiving fallowing command on SMTP handshake from your mail server “530 5.7.1 Client was not authenticated”


I had one of my previous post same issue with Exchange 2007, please do remember, the product exchange is being delivered to you totally secure, and even anonymous access has not been turned on, you as an Exchange administrator must do it.

to understand and see the your server response , you need to open telnet session to your server and use standard SMTP commands to see what is going on so on your exchange server lets start installing Telnet client first

Open DOS or PowerShell and type below

servermanagercmd -install telnet-client


Now on the same screen type

helo  ( hit enter)
220 Microsoft ESMTP MAIL Service
250 Hello []
mail ( Use yours) hit enter
530 5.7.1 Client was not authenticated

As you see the server response is “530 5.7.1 Client was not authenticated


Now lets take care of that, open EMC , go under your Server configuration, hub transport server default receive connector, properties, click on last tab “permission Groups” place check mark into “Anonymous users” click apply and ok.


Now go back to DOS window we opened earlier,

telnet to your mail server on port 25 one more time,

this time you will get

Telnet mail3 25
250 Hello
250 2.1.0 Sender OK

Now your mail server is ready to accept mails from outsidesmile_wink

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Oz Casey Dedeal

MVP (Exchange)
MCSE 2003, M+, S+, MCDST
Security+, Project +, Server + (Blog) (Blog) (Blog)

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