Linux - How to block an ip address on linux server iptables, Block an IP Address using iptable rules

How to block an ip address on linux server iptables

How to block an IP Address on LINUX Server using iptable rules

Use iptables command to add an IP rule to your LINUX firewall. Add an IP table rule block the IP particular ipaddress. You must have root access to add an IP table rule.

Syntax to block an IP address
  iptables -A INPUT -s IP-ADDRESS -j DROP

Example to block an IP address
  # iptables -A INPUT -s 74.12.75.10 -j DROP
Add an IP table rule to block an ip address.

Linux Command to block port 25 of an ip 74.12.nn.10

# iptables -A INPUT -s 74.12.nn.10 -p tcp --destination-port 25 -j DROP

This command will block all the incoming packets to the port 25, of IP Address 74.12.xx.10

After adding the rules the firewall will immediately block the IP Address. If not save the IP tables and then restart the iptables

Command to save the iptables rule
  # iptables-save

  # /etc/init.d/iptables restart

The topic on Linux - How to block an ip address on linux server iptables is posted by - Maha

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