Send-Mailmessage vs Telnet and Non-Accepted Domains

Copper Contributor

Hello Community,


i noticed, that if i try to send an email via telnet to an external domain the session gives me the error "SMTP; Unable to relay recipient in non-accepted domain" - thats good and how you would expect it.


But if i do the same test now with the Powershellcommand Send-Mailmessage the mail is being send to the external recipient.


Can someone explain to my why that works? Where is the difference between the telnet sesssion and the powershell session?


In Telnet i use the commands:
telnet exchange2016fqdn 25
mail from:user@internaldomain

rcpt to:user@externaldomain

SMTP; Unable to relay recipient in non-accepted domain


The powershellcommand looks like this:

Send-MailMessage -to "user@externaldomain" -from "user@internaldomain" -Subject "Test" -body "Test Send-MailMessage" -smtpserver  exchange2016fqdn


With kind regards

Malik Thien

1 Reply
I think i found the answer.

If someone is curious; the powershell is running withing the user context hence using the cerberos token. You can see the sessionauthentication via these commands
$token = [System.Security.Principal.WindowsIdentity]::GetCurrent()

My test-mail was received on the exchange "client proxy"-Receive Connector. In the Security context of that connector Windows Authentication is active so that makes sense i guess.