The spam filtering/mail security system we use for 70 school districts in Western NY blocks attachments with extensions that Microsot has deemed to be unsafe (See http://support.microsoft.com/kb/291369/en-us ), which includes the extension .URL.. A teacher got dropped form a State Ed listserv becuase we rejected (554 5.7.1 Attachments with file extension url are not accepted Message rejected by spam filter) the message at the SMTP level. Is there any advice I can pass on to the list owner on how to block that, and other unsafe extensions, to prevent future problems and make the list safer for all their subscribers? --- In the time it took to read this a Windows exploit was discovered. William Brown Web Development & Messaging Services Technology Services, WNYRIC, Erie 1 BOCES (716)821-7285