Telnet SMTP test email address exists

telnet server.com 25
helo hi
mail from: mail@some-other-server.com
rcpt to: address-to-test@server.com

CORS: Cross-domain AJAX requests

CORS - Cross-Origin Resource Sharing

Server response header:

Access-Control-Allow-Origin: http://www.external-domain.com

Direct AJAX calls to http://www.external-domain.com will not be restricted by the browser.