Carl,
Thanks for this post, this made me go into my mail settings and make sure I had this set. A bit of searching on help tips there led me to this: http://www.msexchange.org/tutorials/Sender-Recipient-Filtering.html which helped my lock down the sending filters further. NDR spam has been the latest headache at my biggest client for the last three weeks or so. Sad that out of 5000 e-mails only 10% is legitimate! I love these kinds of threads, I always learn something... Dave Lum - Systems Engineer [EMAIL PROTECTED] - (971)-222-1025 "When you step on the brakes your life is in your foot's hands" From: Carl Houseman [mailto:[EMAIL PROTECTED] Sent: Monday, March 17, 2008 11:28 AM To: MS-Exchange Admin Issues Subject: RE: NDR setting to send only bounce message without the original message Everyone who receives mail directly at their Exchange 2003 SMTP virtual server should enable "filter recipients who are not in the directory" and tarpitting. Yes, it is effective at blocking NDR spam. Of course if GFI is in front of Exchange then you presumably have a similar setting within GFI, assuming GFI can validate recipients within active directory. Carl ________________________________ From: Kyle Plummer [mailto:[EMAIL PROTECTED] Sent: Monday, March 17, 2008 2:16 PM To: MS-Exchange Admin Issues Subject: NDR setting to send only bounce message without the original message After extricating my domain from an RBL, the tech suggested I change a setting on the mail server to only send the bounce message without the original message. Is this the same as stripping attachments on an NDR? I'm running Exchange 2003 fully patched. I've verified that I'm not an open relay, and only my mail server can send SMTP messages from my network. Is anyone doing Recipient filtering with tar pitting? Is it effective or a pain? I'm using GFI Mail Essentials currently. Any other suggestions for blocking spam, both internally and to prevent our domain from being used as an NDR attack vector? Thanks in advance, Kyle B. Plummer ~ Ninja Email Security with Cloudmark Spam Engine Gets Image Spam ~ ~ http://www.sunbeltsoftware.com/Ninja ~
