Re: Check for blacklists
@LDS: If you are using a VPS to get a static IP address then you can simply set it up as a firewall and tunnel your mailserver's connections to it. That way you get to use an IP address that isn't identified as DSL and but you also retain control of the hardware your mailserver runs on. Win win!
Of course unencrypted mail can be read, though it could be already, but TLS encrypted channels remain secure.