I am installing my easy to install floating cloud email server in AWS Marketplace:
I am in the Final test stages. I have implimented only a small amoiunt of spam protection, however this is enough to block the biggest spammer in the multiverse. The blocked ip address is owned my google and used to send email: nslookup 18.104.22.168
22.214.171.124.in-addr.arpa name = mail-qk1-f182.google.com.
I have installed this on AWS EC2 and requested that AWS lift smtp restrictions. I also use AWS SES. Neither is llisted by sorbs.