When creating mail severs for testing purposes, we too have noticed that many of the IP addresses in the AWS pool are indeed on blaclists or private reputation

When creating mail severs for testing purposes, we too have noticed that many of the IP addresses in the AWS pool are indeed on blaclists or private reputation lists. A smarthost is certainly recommended if you want mail from one of these IP addresses to make it past spam filters. In theory, once you've had the IP address for a while, you should be able to get it delisted and cleared up, but some of these lists and toosl will just block entire subnets that are known to frequently change hands. I think the only real solution would be for Amazon to set aside some IP space and call it premium, and only give it out to validated or longstanding customers, IMHO. @MxToolbox