Following you email, i found 1 big problem in my spamsnake.
I can use a fake user through LAN connection and even through WAN connection
connect to spamsnake and send emails to my domain.
i mean: firstname.lastname@example.org
can send emails to an existing one, e.g email@example.com
How can avoid this to happen?
Answering your post, my MTA behind SpamSnake is Qmail.