Iptables block ftp access
Completely disable the FTP access on the server using below iptables rule:
iptables -A INPUT -p tcp –dport 21 -j DROP
If you want to block FTP access for a Specific IP then run the below command:
iptables -A INPUT -p tcp -s 10.10.10.10 –dport 21 -j DROP
To Disable FTP access for Specific Subnet:
iptables -I INPUT -p tcp -s 10.10.10.10/24 –dport 21 -j DROP
After adding the adding rules you need to save the rules by running the command:
/etc/init.d/iptables save
Then to apply the above saved rules, restart the IPtables by running the command:
/etc/init.d/iptables restart