Send mail from powershell as anonymous user - email

Question

I've always used the cmdlet Send-MailMessage without specifying any -Credential. Now I need to send mail using the anonymous user. The workaround I've found is this piece of code
$pass = ConvertTo-SecureString "anyString"-AsPlainText -Force
$cred = New-Object -TypeName System.Management.Automation.PSCredential -ArgumentList "NT AUTHORITY\ANONYMOUS LOGON",$pass
Send-MailMessage -Credential $cred #...
It works, but is this the correct method to get the anonymous is and send anonymous mail?

Answer 1

You can send mail from any address, it just depends on whether the receiving mail server cares about whether it can verify the sending user or not.
For example if you send from anon#microsoft.com and microsoft does not have that account, OR they have SPF records to indicate whether the sending mail server is valid or not, then the receiving mail server might(not always) reject it.
Just make sure your email user actually exists and has a valid domain... and you can send from anonymous# or noreply# or whatever you want to.

Answer 2

Okay, from the comments we know we're dealing with an Exchange server. Whether or not it will do an anonymous relay depends on the configuration of the Recieve Connectors. But those restrictions only apply to the network connections. If you run Send-MailMessage on the Exchange server and use 'LocalHost' as your SMTPServer it didn't go through a receive connector so those restrictions don't apply.
If you have remoting enabled on the Exchange server you can use that to do a local invocation to send email without having to modify the Receive Connector configurations:
$EmailParams =
#{
To = '<Email To>'
From = '<Email From>'
Subject = '<Email Subject>'
Body = '<Email Body>'
SMTPServer = 'localhost'
}
$Scriptblock = [Scriptblock]::Create(
"Send-MailMessage $(&{$args} #EmailParams) ")
Invoke-Command -ScriptBlock $Scriptblock -ComputerName ExchangeServer