Validating SPF and DKIM at SMTP-time with exim
Debian GNU/Linux System Administration Resources 2015-08-18
Summary:
In our recent articles we've discussed creating SPF-records to avoid spoofed mails, and the creation and setup for DKIM-signing emails, for a similar purpose. Here we'll look at the other side of the coin; performing DKIM and SPF testing on your incoming email.