I am currently using mandrill for sending email for an application of mine but because it places my ip addresses of my backend servers into the headers it makes it impossible to not allow hackers to find my public ip addresses of those servers.
For those who will say the public IP is public and so on. I know that but people do not need to know that is my servers IP. the servers will not respond to ip addresses not part of the cluster. I just want to avoid people finding out "Oh that is your back-end server here is a DNS attack"
Anyone that is knows a provider that does this would be great. I don't mind paying for dedicated IP address. Hopefully sending email wont cost an arm and a leg.