currently another dude is managing it and using fortimail to do that domain whitelisting on the employee mail server, and since the fortinet product license pricing was… kinda doesn’t make sense, i think using kumoMTA is good replacement to the fortimail
This server sits between your users and the wider internet, and your users are highly restricted on what domains they can send mail to, and this list is
At any rate, while that sounds very odd to me, if you configured your listeners to have no relay_hosts you will accept mail from no-one.
If you then used Configuring Inbound and Relay Domains - KumoMTA Docs you could set the domains allowed to relay out to have relay_from directives to lock things down to your authorized network.
That would be a way to do it using helpers, you could of course also write custom Lua code to accomplish this.
it’s kinda like this now on the iredmail
And are you trying to implement the inbound or the outbound?
just for the outbound
Ok, so whitelist usually doesn’t mean “you can only send mail to these recipients” it typically means “those who are whitelisted bypass the normal checks we perform on messages, where non-whitelisted recipients will be subject to scanning and possible filtering”.
In your case you’re sure it’s implemented as “only allow messages outbound to these domains”?
If so what I wrote about relay domains will work.
Yeah, kinda “only allow messages outbound to this domains”
Thanks again for your guys support btw 
I’ll reccomend this MTA to my other colleagues on banking industry since it has amazing features. I’ll ask again if I have question on my mind