Her er hvad der står i dokumentationen til scriptet:
@referers = ('scriptarchive.com','YOUR_IP');
This array allows you to define the domains on which you allow forms to reside and use this installation of FormMail. If a user tries to put a form on another server, that is not scriptarchive.com, they will receive an error message when someone tries to fill out their form. By placing scriptarchive.com in the @referers array, this also allows
www.scriptarchive.com,
ftp.scriptarchive.com, any other http address with scriptarchive.com in it and scriptarchive.com's IP address to access this script as well, so no users will be turned away.
NOTE: This is not a security check. Referer headers can EASILY be faked. Rather, it prevents someone on xyznotyou.com from using the FormMail on your server to process forms on their server on a regular basis. It remains in the script as a remnant of earlier versions when it was used for security, but the @recipients variable is now used to specify exactly who can receive e-mail from this installation.
As of version 1.7, the domains listed here are also used as the defaults when checking valid recipient e-mail addresses. You should either include all domain names that you wish to have FormMail send e-mails to in your @referers array or tailor the @recipients array by hand.