الان یه چیزی رو توی csf چک کردم:

SMTP Settings

Block outgoing SMTP except for root, exim and mailman (forces scripts/users
to use the exim/sendmail binary instead of sockets access). This replaces the
protection as WHM > Tweak Settings > SMTP Tweaks

This option uses the iptables ipt_owner/xt_owner module and must be loaded
for it to work. It may not be available on some VPS platforms

Note: Run /etc/csf/csftest.pl to check whether this option will function on
this server

SMTP_BLOCK = 1 Default: 0 [0-1]

If SMTP_BLOCK is enabled but you want to allow local connections to port 25
on the server (e.g. for webmail or web scripts) then enable this option to
allow outgoing SMTP connections to the loopback device

SMTP_ALLOWLOCAL = 0 Default: 0 [0-1]

This is a comma separated list of the ports to block. You should list all
ports that exim is configured to listen on

SMTP_PORTS = 25,465,587

Always allow the following comma separated users and groups to bypass
SMTP_BLOCK

Note: root (UID:0) is always allowed

SMTP_ALLOWUSER =
SMTP_ALLOWGROUP = mail,mailman