Result of DROP is Connection Refused
Iptables is a firewall, installed by default on all official Ubuntu distributions (Ubuntu, Kubuntu, Xubuntu). When you install Ubuntu, iptables is there, but it allows all traffic by default. Ubuntu comes with ufw – a program for managing the iptables firewall easily.
- Reject Specific IP in iptables
sudo iptables -I INPUT -s 111.111.111.111 -j DROP
- Show IP List in iptables
iptables -L INPUT --line-numbers
Chain INPUT (policy ACCEPT)
num target prot opt source destination
1 DROP all -- 111.111.111.111 anywhere- Delete IP on IP List in iptables
iptables -D INPUT 1
- Flushing the List in iptables
sudo iptables -F -t nat -v
Flushing chain PREROUTING'
Flushing chain INPUT'
Flushing chain OUTPUT'
Flushing chain POSTROUTING'