Send email with PowerShell

Easily send your DevOps reporting by email with this PowerShell function, because the Send-MailMessage cmdlet is obsolete. Of course you’ll be using StartTLS and authenticated SMTP as additional security.

If you’re trying to send an email using the Send-MailMessage cmdlet, it throws a warning on your shell:

WARNING: The command ‘Send-MailMessage’ is obsolete. This cmdlet does not guarantee secure connections to SMTP servers. While there is no immediate replacement available in PowerShell, we recommend you do not use Send-MailMessage at this time. See https://aka.ms/SendMailMessage for more information.

Time for something else, right?

In this post I provide you with a small PowerShell function you can use as to send email over an secured SMTP connection with SMTP authentication and StartTLS. As a framework you can use it in your own scripting, extend it, and you can even turn it into a PowerShell module. The mail function is quite rudimentary and has a lot of assumptions in it. All provided AS-IS.

PowerShell function to send SMTP email

You can use the following function to send a basic email to an email address of your choosing. On your shell, or command line interface / cli, it prompts you for your SMTP authentication password. This way, using a SecureString, your password is not saved in PowerShells history file $env:APPDATA\Microsoft\Windows\PowerShell\PSReadLine\ConsoleHost_history.txt.

Function Send-MyMailMessage($from, $to) {
  $mailFrom = "${from}"
  $mailTo = "${to}"
  $Subject = "Test email"
  $Body = "This is my email message"
  $SMTPServer = "smtp.example.com"
  $SMTPClient = New-Object Net.Mail.SmtpClient($SMTPServer, 587)
  $SMTPClient.EnableSsl = $true
  $ww = read-host -AsSecureString "Provide your email password."
  $SMTPClient.Credentials = New-Object System.Net.NetworkCredential("${from}", "$(${ww} | convertfrom-securestring -AsPlainText)");
  $SMTPClient.Send($EmailFrom, $EmailTo, $Subject, $Body)
}
Code language: PowerShell (powershell)

Be sure to change the SMTP server address on line 6, and maybe the SMTP port 587 on line 7.

When you call Send-MyMailMessage with arguments $from and $to, like:

Send-MyMailMessage jan@example.com admin@example.net
Provide your email password.: *****************Code language: PowerShell (powershell)

and you fill out your SMTP authentication password, an email is sent to admin@example.net with jan@example.com as the sender’s from address.

Instead of using .NET’s SMTP Class Net.Mail.SmtpClient, you can also use and reference MailKit. I created a small .NET MailKit example on ITFAQ.nl (in Dutch).

Such a small, and rather static, PowerShell mail sending function is ideal for DevOps reporting. Of course you can expand the function with additional input variables and command line arguments, etc.

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