[sieve] Restrict redirects to only own domain

[Stephan Bosch]

Op 16/10/2018 om 12:42 schreef Yassine Chaouche:
> Hello list,
>
> I'd like to let my colleagues redirect mail automatically (via a sieve 
> filter) to other mailboxes within the same domain, but deny redirects 
> to outside mailboxes (gmail, yahoo etc.) since this is considered bad 
> practice and could lead to blacklisting (forwarding spam for example).
>
> If I set sieve_max_redirect to 0 then no redirect is allowed, at all. 
> I wish to let redirects to internal mailboxes still possible.
>
> Ideas ?

The redirect action implicitly adds an X-Sieve-Redirected-From header. 
You could block such e-mails from being routed outside your domain in 
your MTA. I believe most MTAs have routing features that would support 
doing this.

Regards,

Stephan.