[root@golf2 ~]# /etc/csf/csftest.pl
Testing ip_tables/iptable_filter...FAILED [FATAL Error: iptables v1.8.4 (nf_tables): CHAIN_ADD failed (Device or resource busy): chain INPUT] - Required for csf to function
Testing ipt_LOG...FAILED [FATAL Error: iptables v1.8.4 (nf_tables): CHAIN_ADD failed (Device or resource busy): chain INPUT] - Required for csf to function
Testing ipt_multiport/xt_multiport...FAILED [FATAL Error: iptables v1.8.4 (nf_tables): CHAIN_ADD failed (Device or resource busy): chain INPUT] - Required for csf to function
Testing ipt_REJECT...FAILED [FATAL Error: iptables v1.8.4 (nf_tables): CHAIN_ADD failed (Device or resource busy): chain INPUT] - Required for csf to function
Testing ipt_state/xt_state...FAILED [FATAL Error: iptables v1.8.4 (nf_tables): CHAIN_ADD failed (Device or resource busy): chain INPUT] - Required for csf to function
Testing ipt_limit/xt_limit...FAILED [FATAL Error: iptables v1.8.4 (nf_tables): CHAIN_ADD failed (Device or resource busy): chain INPUT] - Required for csf to function
Testing ipt_recent...FAILED [Error: iptables v1.8.4 (nf_tables): CHAIN_ADD failed (Device or resource busy): chain INPUT] - Required for PORTFLOOD and PORTKNOCKING features
Testing xt_connlimit...FAILED [Error: iptables v1.8.4 (nf_tables): CHAIN_ADD failed (Device or resource busy): chain INPUT] - Required for CONNLIMIT feature
Testing ipt_owner/xt_owner...FAILED [Error: iptables v1.8.4 (nf_tables): CHAIN_ADD failed (Device or resource busy): chain INPUT] - Required for SMTP_BLOCK and UID/GID blocking features
Testing iptable_nat/ipt_REDIRECT...OK
Testing iptable_nat/ipt_DNAT...OK
RESULT: csf will not function on this server due to FATAL errors from missing modules [6]
I already have NETFILTER enabled which is suggested on https://wiki.openvz.org/Setting_up_an_i ... figuration