Simple Python script as SMTP server for outgoing e-mails?

[Chris Angelico]

On Tue, Jul 23, 2013 at 8:06 PM, Duncan Booth
<duncan.booth at invalid.invalid> wrote:
> Excellent idea, I'll tell the email forwarding service to rewrite their
> system immediately.

Yes. If they are using your domain in the MAIL FROM command and not
using your mail servers, then yes, you should tell them, and use a
different service until they fix that. It is not SPF's fault. It is a
fundamental error of protocol, which SPF checks are highlighting.

ChrisA