Ok.... I followed this below in shell
# Note: Run /etc/csf/csftest.pl to check whether this option will function on
# this server
Results returned the following
[email protected] [~]# /etc/csf/csftest.pl
Testing ip_tables/iptable_filter...OK
Testing ipt_LOG...OK
Testing ipt_multiport/xt_multiport...OK
Testing ipt_REJECT...OK
Testing ipt_state/xt_state...OK
Testing ipt_limit/xt_limit...OK
Testing ipt_recent...OK
Testing xt_connlimit...OK
Testing ipt_owner/xt_owner...OK
Testing iptable_nat/ipt_REDIRECT...OK
Testing iptable_nat/ipt_DNAT...OK
RESULT: csf should function on this server
So I disabled the SMTP Tweak in cPanel and enabled the one in CSF.
I do not know which SMTP Tweak would preform better CSF or cPanel?
Can someone who has experience with this explain the differences please.