simple security

In most of the corporate networks, these days, they dont allow you to mail executable files like .exe, .scr, .dll etc. The mail filter on the server is going to detect that you tried to send out an executable and bounces back the mail in your inbox. Sometimes zipping up the file before attaching it to the email does the trick. But these days the mail filters are getting smarter and can look inside a compressed file as well.

This is mainly done for security reasons. In the past few years, the network admins have learnt that viruses and/or spammers trick the users into clicking on executable stuff in the mail and then take advantage of buffer overflow exploits.

So what do you do if you really really want to send someone an exectuable attachment? If you use PGP, GPG, or S/MIME to encrypt your mail before sending it out, then it would sail right past the mail attachment blocking filters.

ps: If you want a free personal digital certificate to use S/MIME, check this out from Thwate: http://www.thawte.com/html/COMMUNITY/personal/index.html