SSSIHL tied up with Benchmark for sending some 4000 emails, they wanted to make it into a newsletter every couple of months. There were multiple issues with the email sending.
- The first time around, the sssihl.edu.in SPF record had not been updated to include benchmark servers, which resulted in spam filtering blocks for most of the mails. Along with SPF update, Benchmark also recommended whitelisting the Benchmark mail server IPs for sssihl.edu.in mail servers.
- Found that Google Apps allows whitelisting. Updated the SPF record.
- Then found that the SPF record was returning an error, too many lookups, via the test at http://www.kitterman.com/spf/validate.html - googling showed that having Godaddy's include:smtp.secureserver.net in the SPF record causes a very large number of lookups. Moved the sending of emails from the Godaddy server to google apps, removed that include, then the SPF validated.
Finally most of the emails went through after the valid SPF.