Forum OpenACS Q&A: Re: email relay
Suspending notification handling:
- Notification is handled by sweep_notifications, registered by , if you disable (i.e. comment out) the registry of the schedules procedures, this processing stops.
- in general different delivery methods are allowed configured, default is "email", and the delivery works over 
Suspending outgoing emails:
- mail sending works for non immediate cases vial a mail queue, which is processed via acs_mail_lite::sweeper 
- one can deactivate the sweeper by commenting out the
registry of the scheduled procedure in 
Deactivating schedules procedures can also be done by getting the scheduled id (e.g. via nsstats) and unregister the scheduled proc.
One can also deactivate mail queue processing temporarily (without server stopping) be setting the nsv "acs_mail_lite send_mails_p" to a value larger than 0, telling the sweeper, that it should not process it.
For configuring SMTP delivery, the following parameter in acs-mail-lite can be used: SMTPHost, SMTPTimeout, SMTPPort, SMTPUser, SMTPPassword. Adjusting these parameter should be sufficient for most mail relays.
Hope this helps