Vlinder Software has deployed SPF DNS records on the vlinder.ca domain, tagging any E-mail not sent by one of the mail servers we normally use as a “soft failure”.
In light of our project to roll out spam prevention measures we’ve implemented the first SPF record on our own domain, vlinder.ca.
We’re starting with vlinder.ca for three reasons: First, we own the domain and can measure the risk of implementing this anti-spam measure without affecting the domains of the small businesses and charities we manage the other domains for; Second, the vlinder.ca has relatively little out-going E-mail but that E-mail does come from a variety of sources (web apps, mobile devices, PCs). We have a fairly good record of the E-mails we send and can track fairly well which are received, so we can measure the impact of deploying SPF. Third, the only spam messages we’ve been able to confirm had spoofed the email@example.com address. As far as we know, none of the other domains we manage have been abused like this yet.
It can take up to 48 hours for the new DNS entries to propagate through the Internet, and we will be conducting a few tests after that, so deployment of SPF in the next domain(s) is scheduled for next week.