From: Rich Matheisen [MVP] on
On Thu, 20 May 2010 04:31:01 -0700, MM <MM(a)>

[ snip ]

>Actually GFI is configured to perform Directory Harvest filtering not at the
>SMTP level. Exchange should be doing Recipient filtering before GFI gets the
>To be sure they're not conflicting I disabled GFI DH filter, but I still get
>a Recipient OK reply instead of the SMTP connection error.
>Our organization is expressly required to send a SMTP connection error on
>RCPT TO:non-existent, that's why I'm trying to make Exchange Recipient
>filtering work.
>From what I've seen GFI would block an email for all recipients when the
>configured non-existent-users threshold is reached: setting the threshold to
>1 would be too restrictive and >1 doesn't fulfill our requirement, so I'm
>afraid we can'use this option.

Does get-transportagent show the "Recipient Filtering Agent" to be
enabled? And at which position in the array of agents is the recipient
filtering agent? Are there multiple agents doing the same job (e.g.
ForeFront Protection Manager)?

Check the "message delivery" tab on the "Transport Settings" property
page. You'll find that on the "Global Settings" tab of the "Hub
Transport" node in the "Organization Configuration" of the EMC. Or you
can just run "get-transportconfig | fl InternalSMTPServers".

Have you checked the SMTP Receive log on the server? Are the IP
addresses of the sending servers in the "InternalSMTPServers" set of
Rich Matheisen
MCSE+I, Exchange MVP
From: MM on
Thank you for your helpful information.

IT management has decided for an antivirus and antispam software upgrade +
Exchange SP2 installation, so we have suspended testing on recipient
filtering until the above are ok.

I'll bring you up to date as soon as I can work on the configuration.

Thank you