How this form is built
The email field is watched by js/email-domain-blocker.js in
block mode β the same script described in the
administrator guide β so submission is
refused client-side for a Microsoft-hosted address. The form posts to a
small CGI script, cgi-bin/contact.cgi, which repeats the same
domain check server-side (client-side JavaScript is never sufficient on its
own β see the guide for why) before emailing the submission on.