To find out if an IP address is banned in Linux using iptables, you can use the following command:
iptables -nL --line-numbers | grep <IP address>
This will show you the list of rules in the iptables firewall and highlight the line containing the specified IP address. If the IP address is banned, you should see a rule that blocks incoming traffic from that IP address.
For example:
iptables -nL --line-numbers | grep 192.168.1.100
This will show you the list of iptables rules and highlight the line containing the IP address 192.168.1.100
.