On Thu, Jan 13, 2011 at 08:45:19AM -0600, Noel Jones wrote:
> Once the cows get out, you can spend days rounding them up and some may
> never be found. Better to keep the gate closed.
>
> Corollary: Don't accept mail you can't deliver.
For a submission service, this means doing as much as possible to reject
spam/malware, rate-limit authenticated senders, ... Also if the service
is intended to support MUA users, not MTAs validating the sender address
against the sender login will thwart sender address forgery in outbound
mail.
http://www.postfix.org/SASL_README.html#server_sasl_authz
For inbound mail to the OP's own domain, recipient address validation
via suitable tables is a must.
http://www.postfix.org/ADDRESS_CLASS_README.html
--
Viktor.
