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Everything You Need to Know About Fail2Ban

No application can be considered completely secure. Majority of them have flaws and weak areas, leaving doors open for security threats. You can opt for various solutions to secure your data. One of the most well-known ways is by using Fail2Ban.

What is Fail2Ban?

The obvious definition of this application includes monitoring the logs of common services and looking for malicious signs. It scans the log files and automatically bans the IPs with suspicious activity (e.g. a large number of failed login attempts) . These might include exploitations, password failures, etc.

Another Fail2Ban feature is to update the firewall rules. It comes with various filters, including apache, ssh, courier, etc. Each of them serves a different purpose and can be configured.

How to Use Fail2Ban to secure your server?

Now that you know what Fail2Ban is, let’s see how to use Fail2Ban to secure your server. Check this comprehensive Fail2Ban configuration guide. After installing the application, log in to your server. Use SSH for this.

When the command prompt opens, type this command:

cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local

  1. Now, open the jail.local file in any text editor.
  2. Navigate to the DEFAULT section.
  3. Next, you are ready to enable and disable jails for selected protocols. When installed, it is set to SSH monitoring as default. You can search for this specific section to make changes.
  4. Once you are done, save the jail.local file.

estart the Fail2Ban service to load these new configurations. You can do this simply by typing the following command:

service fail2ban restart

What Is Fail2Ban Used For?

As mentioned earlier, Fail2Ban is used to protect SSH. However, there are many more options to use this log parsing app. So what else is Fail2Ban used for?

  • WordPress security. It works effectively against hackers and security threats.
  • Single Packet Authentication (SPA). Fail2Ban is used with fwknop to provide a higher level of protection. You can also use the port-knock server knockd for the same purpose. It monitors all the traffic on an ethernet interface and looks for sequences of port-hits. Since it listens at the link-layer level, knockd can be used to discover firewall holes.

Fail2Ban Alternatives

CrowdSec - this name immediately comes to mind when talking about Fail2Ban alternatives. This solution is a free behavior detection engine, which works similar to Fail2ban. The key difference, however, is that it takes the game one step further with its IPV6 Compatibility and quick speed.
It checks all the IPs before sharing them among users. Thus, you can easily detect the malicious ones and improve security.

Given the information above, we can say that Fail2Ban is one of the most effective log-parsing applications out there. This solution is efficient and straightforward. However, it can not replace security platforms, such as Wazuh, Ossec, Splunk, et al.