iptables -t nat -n -L
Please note that it is often used with the -n option, in order to avoid long reverse DNS lookups.
-n, --numeric
Numeric output. IP addresses and port numbers will be printed in numeric format. By default, the program will try to display them as host names, network names, or services (whenever applicable).
fail2ban добавляет именно IP-адреса, но когда вы просматриваете
iptables -nvL
