AFAIK, this should be simple. Block mail from your domain in the smtp con. Internal mail does not use the smtp con... Not tested, but logically I think it should work. Anyone care to elaborate? jlc
-----Original Message----- From: Tom.Gray [mailto:[EMAIL PROTECTED]] Sent: Monday, June 03, 2002 11:48 AM To: MS-Exchange Admin Issues Subject: How to anti-spoof in exchange 5.5???? This may be impossible or very easy. I'm not an expert in Exchange so please be gentle! Problem -- Klez is killing us. Not the actual virus, but the spoofed emails. People on my network receive mail that LOOKS like it is from someone on my network (the basic KLEZ spoof) but they just won't accept the the explaination that it is a faked return address. I KNOW this is a user education issue. But, can I configure my exchange server so that the smtp connector rejects any email from the outside world that has a FROM address of one of my inside folks? Hmm, how about an example: assume my smtp domain is: mydomain.com So [EMAIL PROTECTED] is a user on my network. He uses my exchange server to send messages. Now, somebody outside my network gets the KLEZ virus and sends a message (from outside my network) to somebody on my network, but the message has the FROM field filled with [EMAIL PROTECTED] Can I make the smtp connector reject those messages? Thanks for helping Tom Gray, Network Engineer All Kinds of Minds & The Center for Development and Learning University of North Carolina at Chapel Hill Internet: [EMAIL PROTECTED] AT&T Net: (919)960-8888 List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm List Charter and FAQ at: http://www.sunbelt-software.com/exchange_list_charter.htm