What if you close port 25 tightly?

Question

Mail server

The question is this - out of the entire pool of sites on my VPS, only 1 uses postfix to send notifications and this is a roach forum. The rest of the sites use PDD from Yandex and as such I don’t need my own mail server, one headache from it ...
You can close port 25 from everyone, but so that there is only outgoing mail, it’s not used at all, only spammers hammer :(
What do you advise ?

Answer 1

close

Answer 2

What if you close port 25 tightly?

There will be a tightly closed port :)