requirements
Google are circulating a new set of requirements for bulk senders on their blog. So are Yahoo. It’s almost like postmasters talk to each other or something. If you dig through the links in the Gmail blog post you can find this summary of what they’ll be requiring from bulk senders by February: Set up SPF or DKIM email authentication for your domain. Ensure that sending domains or IPs have valid forward and reverse DNS records, also referred to as PTR records. Learn more Keep spam rates reported in Postmaster Tools below 0.3%. Learn more Format messages according to the Internet Message Format standard (RFC 5322). Don’t impersonate Gmail From: headers. Gmail will begin using a DMARC quarantine enforcement policy, and impersonating Gmail From: headers might impact your email delivery. If you regularly forward email, including using mailing lists or inbound gateways, add ARC headers to outgoing email. ARC headers indicate the message was forwarded and identify