Dear List, I am running Exchangr 5.5 sp4 onNT4 sp6a (128bit). I have secured the server against spam (What I think). But whenever I check the outbound queue in the IMS, there lots of ambigous e-mails being seen. An example is: A mail message could not be sent because the following host is unknown: mail4.wyzermail.com The message that caused this notification was: To: <bounce-110205856-2580@xxxxxxxxxxxxxxxxxxx> From: <> Subject: Undeliverable: Need $24,000 in 24 hours? I don't know where these mail are being generated from. Any Ideas.... Regards, Chand Deshwal (M.Tech CS&E, MCSE, CCNA) IT Manager Kampsax India (P) Ltd., 809, Phase-V, Udyog Vihar, Gurgaon E-Mail: CDD@xxxxxxxxxxxxx Web: http://www.kampsaxindia.com Ph: +91 124 5092500, Extn.12 Direct: +91 124 5092512