Also have a look at the manual options in the /etc/virtual directory.
-rw-r----- 1 mail mail 246 2023-02-13 14:58 bad_sender_hosts
-rw-r----- 1 mail mail 401 2023-02-20 00:14 bad_sender_hosts_ip
-rw-r----- 1 mail mail 374 2021-07-13 21:00 blacklist_domains
-rw-r----- 1 mail mail 106 2021-07-01 19:35 blacklist_senders
-rw-r----- 1 mail mail 114 2022-03-26 01:15 whitelist_domains
-rw-r----- 1 mail mail 22 2019-07-23 19:49 whitelist_from
-rw-r----- 1 mail mail 48 2019-07-23 19:49 whitelist_hosts
-rw-r----- 1 mail mail 71 2022-03-26 01:16 whitelist_hosts_ip
-rw-r----- 1 mail mail 22 2019-07-23 19:50 whitelist_senders
I've installed spamassassin and spamblocker and easy spamfighter.