No ubuntu 20 houve uma mudança de diretórios do iptables dando erro na inicialização do CSF:
*Error* The path to iptables is either not set or incorrect for IPTABLES [/sbin/iptables] in /etc/csf/csf.conf at /usr/local/csf/lib/ConfigServer/URLGet.pm line 26.
Compilation failed in require at /usr/sbin/csf line 21.
BEGIN failed--compilation aborted at /usr/sbin/csf line 21.Em alguns casos pode ser necessário instalar o iptables por ausência dele
sudo apt-get install iptablesAcesse o Arquivo de configuração do CSF:
nano /etc/csf/csf.confLocalize;
IPTABLES = "/sbin/iptables"
IPTABLES_SAVE = "/sbin/iptables-save"
IPTABLES_RESTORE = "/sbin/iptables-restore"
IP6TABLES = "/sbin/ip6tables"
IP6TABLES_SAVE = "/sbin/ip6tables-save"
IP6TABLES_RESTORE = "/sbin/ip6tables-restore"Substitua por:
IPTABLES = "/usr/sbin/iptables"
IPTABLES_SAVE = "/usr/sbin/iptables-save"
IPTABLES_RESTORE = "/usr/sbin/iptables-restore"
IP6TABLES = "/usr/sbin/ip6tables"
IP6TABLES_SAVE = "/usr/sbin/ip6tables-save"
IP6TABLES_RESTORE = "/usr/sbin/ip6tables-restore"Salve e reinicie o CSF
csf -r