[exim] How to check all options can be set?

Hi Folks,

How can I find all directives/options can be set in one section? (Link for
MAIN instruction ...)

For example, here can I use: helo_data, interface, event_action...

begin transports

remote_smtp:


And another option is? I need to do some checks at this section and, in
some cases, refuse one email.

I need to do one "lookup" to refuse email based on my mysql instructions
but I don't know how to use that. For example in other sections can I use "
condition" but inside remote_smtp I can't.

Thanks,

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* Otávio Nogueira