remove "HELP" command from SMTP command (Windows server)

Question

Dears

As below :

220 XXX.XXX Ready

HELP

214-This server supports the following commands:

214 HELO EHLO STARTTLS RCPT DATA RSET MAIL QUIT HELP AUTH BDAT

I need to to remove "HELP" command from SMTP command (Exchange Windows Server) because of security reasons. would you please tell me how can i do it ?

Thank You

Answer 1

There isnt really a way to remove just that command on the receive connector as far as I know.

You have a few options you can test out - but these options will disable all the ESMTP verbs

For the receive connector:

https://learn.microsoft.com/en-us/powershell/module/exchange/set-receiveconnector?view=exchange-ps

EnhancedStatusCodesEnabled

Set this to false
-EnhancedStatusCodesEnabled
The EnhancedStatusCodesEnabled parameter specifies whether the ENHANCEDSTATUSCODES Extended SMTP extension is enabled or disabled on the Receive connector. Valid values are:

$true: ENHANCEDSTATUSCODES is enabled and is advertised in the EHLO response. This is the default value.
$false: ENHANCEDSTATUSCODES is disabled and isn't advertised in the EHLO response.

For the Send Connector:

-ForceHELO
The ForceHELO parameter specifies whether HELO is sent instead of the default EHLO. Valid values are $true or $false. The default value is $false.

https://learn.microsoft.com/en-us/powershell/module/exchange/set-sendconnector?view=exchange-ps

Answer 2

Thank you. I found this solution for Linux Servers:

To disable the SMTP HELP command, clear the Sendmail help file.

echo > /etc/mail/helpfile

But I'm Looking for a solution to disable it on windows Server. Isn't there any solution to only disable help command?

Answer 3

If you are running "Exchange Windows Server" as you stated above, there is no "SMTP service" per se. Its handled by the Exchange Transport Service.
I know of no way to just disable that command within Exchange.