How is it: mynetworks = 127.0.0.0/8 yet local network users are able to send.

[Sthu Pous]

Good day.

Could You please, explain me how it is possible for the users from local net to
send mail if we have in main.cf:

mynetworks = 127.0.0.0/8

?

And moreover, how I can reduce the mail sending only for the users (their IPs
and authorization) so that at the same time the users could get their emails
from outside world?

Thank You for Your time.