[Dovecot] Force STARTTLS on port 143 for !internalnetwork

[Nick Rosier]

Ralf Hildebrandt wrote:
> Hi!
>
> How can I force users which are connecting from OUTSIDE our newtworks
> to user STARTTLS on Port 143?
>
> Right now we resort to IMAPS on port 993, but an additional STARTTLS
> enabled login on the default port would make things easier!
>
You can probably add login_trusted_networks = localnet

IIRC this allows for unsecure login from your localnet but forces all 
other networks to use a secure authentication method (e.g. SSL, 
STARTTLS, CRAM or DIGEST).

N.