Email marketers should begin attending to Sender Policy Framework (SPF) authentication to improve email deliverability.

A new study showed that SPF checks are becoming part of content filtering tests done by Internet service providers. These checks involve comparing the sender’s return path domain and the IP address to a list of approved IPs the sender includes in their DNS zone.

The Lyris’ EmailAdvisor ISP Deliverability Report Card for Q2 2007 measured the delivery path of more than 436,000 permission-based e-mail marketing messages using ISP domains in the United States, Canada, Europe and Australia.

Changes in IP addresses or email service providers without updating SPF records could possibly increase the chance of failure when passing content filters. Marketers need to ensure that their SPF records are current to maintain deliverability.