Most mail scripts use a system program called sendmail to send form mail. All of our UNIX/Mac OS X servers run sendmail in submit-only mode to permit form processing. However, they are configured so that you must use the "-f" flag to set a "from" address on the outgoing message; this prevents many form vulnerabilities that allow spammers to hijack CGI scripts.

In the configuration for your script, there are two things you'll want to check

• The "Path to sendmail" should be /usr/sbin/sendmail
• Our servers are configured so that so that you must use the -f flag to set a "from" address on the outgoing message; this prevents many form vulnerabilities that allow spammers to hijack CGI scripts.

  The proper syntax is -f (from address) -- eg -f john@doe.com

  Most scripts will let you specify this in an "optional paramaters" or "sendmail flags" section. See the documentation for your specific script for more details.
  

If you're using PHP, please see How can I make my PHP form process work using the mail() function?