We would eventually like twistedmatrix.com mail to be self hosting with twisted.mail.
The requirements we have
- Mailing list hosting using mailman.
- Delivery of local mail. This is primarily for trac.
- Forwarding of mail for aliases on twistedmatrix.com.
- Delivery of outgoing mail for authorized users. This would be a prerequesite for doing things like setting SPF.
There is currently some (untested) code to interact with mailman and greylistd at https://github.com/twisted-infra/t-mail.