After previously using managed ESP's, we've recently switched over to our own server (CentOS 6) that's set up to send bulk e-mails with 12 IPs/SPF/DKIM. Campaigns are processed and sent via Interspire, but I've been testing with a desktop application also. Starting from fresh reputation was new for us, but we've been sending out 10/15k a day for the first week (in line with a lot of stuff about reputation building online). What's troubling me is that we're suffering from extremely low open-rates (1% - 3%, compared to 20% - 25% on the same lists with the same content from a managed ESP). I noticed that 2 of the IP's didn't have a correct rDNS setup, so that is being fixed by devs now, but surely that can't wholly account for the terrible rates I'm seeing? Mail-Tester.com is showing e-mails sent as 10/10 (everything correctly configured). SenderScore.org is showing all IPs as > 90 sender score (apart from the 2 with incorrect rDNS, which are showing as in the 60s) From this afternoon, mail I send (multiple attempts) isn't even landing in Hotmail's inbox. It lands in Yahoo fine, but where it goes (inbox or spam) is random, presumably due to the couple of bad IP setups. My questions are: 1. Where am I going wrong? 2. How can I better troubleshoot the issue? 3. Is there a better method for building up and maintaining inbox rates to major email providers?