Block Brute Force in SMTP

RouterOS General
1

H
I need to block excess brute force in SMTP with access denied. By sniffer identified that the package receives the return 554 5.7.1 <mail@domain.com>: Relay access denied. I tried to place the lock through Firewall Filters using the “Content”, but without success. Anyone have any suggestions or example?

Tks

2

You can use the same technique used to prevent SSH brute forcing, dynamic address lists.