problems with forwarding mail / throttling mail from mynetworks

[Rune Elvemo]

Hi.

We are implementing postfix as “front mail servers”. Their job will be 
to relay email to our inside servers, and be the “smart host” for all 
internal servers.

I thought that as long a domain was registered as a relay-domain, 
postfix would send emails both ways for this domain. But I discovered 
that only inbound emails are forwarded when the domain is registered in 
relay-domains, and that the sender must be in mynetworks to send 
outbound email.

However… When a sender is registered in mynetworks, all the security 
features, like throttling, are bypassed. I would like Postfix to do all 
the same checks and the same throttling on email from mynetwork. Is that 
possible?
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Rune Elvemo