Preferably as soon as the account is created, its best to enable DKIM and SPF, located in the EMAIL section.
Otherwise its possible (and very easy) to send outgoing mail through any domain name, using telnet on the SMTP port.DKIM
DKIM is a means of verifying incoming email. It ensures that incoming messages are unmodified and are from the sender from whom they claim to be. This feature works to prevent incoming spam messages.
The SPF system allows you to specify servers and IP addresses that are authorized to send mail from your domain(s). This feature works to prevent outgoing spam messages.
Is there a way to automatically enable DKIM and SPF with all cpanel account creations? Maybe something to drop into the cpanel-skel folder?