How To Block IP Addresses On Linux Server

Take a look at your log file (/var/log/secure for Fedora Core 4) and you will discover numerous automated ssh hacking attempts using dictionary attack. So now you have identified the offending addresses. How do you stop them?

Here comes the magic mantra which uses iptables (packet) firewall:

iptables -A INPUT -s a.b.c.d -j DROP

Replace a.b.c.d with the offending IP address. Repeat this for each of the offending IP addresses.

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