How to block spam from your domain in ORF?

Question

Email

Good afternoon.
The organization has 1 Exchange 2010 sp2 server, and there is 1 edge server (connector). It also sends and receives letters. Recently, periodically, spam comes from mailboxes with the sender's address from my domain. Can anyone suggest how you can protect yourself from such a substitution of senders in spam emails and reject them?

Answer 1

1. Change SPF from soft-fail to hard-fail:
v=spf1 mx -all (minus "-" instead of
tilde "~")
your domain (then add them to spf).
Enable SenderID on edges (assuming EDGE is the first edge server to receive mail).
After that, spoofing should disappear as a class.
2. How to workaround - set up transport rules - create a box for pre-moderation of such letters - set up transport rules if mail comes from your domain and from outside - send it for pre-moderation.

Answer 2

Good afternoon
Maybe you need to register spf-record in dns