Block ip address of spammers with iptables under Linux

Q. How do I block ip address of spammers with iptables based firewall under CentOS Linux 5?

A. You can simply block IP address of spammers by editing /etc/sysconfig/iptables file under:

a) CentOS Linux
b) Fedora Linux
c) RHEL 4.x/5.x etc

Open file /etc/sysconfig/iptables:
# vi /etc/sysconfig/iptables
Append ip address of spammers as follows:
-A RH-Firewall-1-INPUT -s SPAMMER-IP -j DROP
-A RH-Firewall-1-INPUT -s SPAMMER-SUBNET-BLOCK -j DROP

Save and close the file. Just restart the firewall:
# /etc/init.d/iptables restart

You can also create a small shell script to block lots of IP address at a time.

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{ 2 comments… read them below or add one }

1 Andy 09.25.07 at 7:20 pm

Hi

Do you know of any way that it does it automatically by getting a list of known spammers from the internet?

2 kunal 10.15.07 at 6:16 am

How to automatically block a user after multiple failed sshd logins say after 3 failed logins
for temporary time say 2 days.

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