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Do I need Fail2ban if I use ssh keys?
I would recommend changing your SSH Keys every few years (to ensure you’re using “current” technology, and to verify documentation surrounding the system). Fail2ban is not just for ssh brute-force attacks. If you have Apache, Postfix, Dovecot or other services supported by Fail2ban then you can protect those services.
Is Fail2ban necessary?
Depending on what you’re doing on the server, an application firewall like fail2ban (or ModSecurity) could provide additional security for other internet-facing services running on the machine (but to answer your question, no, fail2ban would not provide any meaningful amount of additional security for key-based ssh).
What can Fail2ban do to protect sshd?
You can setup Fail2Ban to provide brute-force protection for SSH on your server. This ensures that your server is secure from brute-force attacks. It also allows you to monitor the strength of the attacks in regards to the number of authentication attempts that are being made.
How do I start fail2ban?
Configuring fail2ban
- Log in to your server using SSH.
- At the command prompt, type the following command: cp /etc/fail2ban/jail.conf /etc/fail2ban/jail.local.
- Open the jail.
- Locate the [DEFAULT] section, which contains the following global options:
- Save your changes to the jail.
How do I know Fail2ban is working?
log if fail2ban has been started. You’ll also see output related to fail2ban activity. If you installed failed2ban via the package manager or software center, you should see entries in the /etc/rc* directories for fail2ban, which indicate (on default settings and without customization) that it will run on startup.
How does Linux Fail2ban work?
Fail2ban works by dynamically altering the firewall rules to ban addresses that have unsuccessfully attempted to log in a certain number of times.
How to limit failed ssh login attempts with Fail2Ban?
With the standard configuration fail2ban will protect SSH server and will block the malicious party for 10 minutes after 5 failed login attempts within 10 minutes timeframe. The default config file can be found at /etc/fail2ban/jail.conf.
What do you need to know about Fail2ban?
With the default settings, Fail2ban will ban a client that unsuccessfully attempts to log in 3 times within a 10 minute window. If you wish to configure email alerts, you may need to override the destemail, sendername, and mta settings. The destemail parameter sets the email address that should receive ban messages.
Is the ssh port pre defined in Fail2ban?
In this case, ssh is a pre-defined variable for the standard SSH port, and % (sshd_log)s uses a value defined elsewhere in Fail2ban’s standard configuration (this helps keep jail.conf portable between different operating systems).
Where is the default config file for Fail2ban?
The default config file can be found at /etc/fail2ban/jail.conf. The file is well documented and mostly self-explanatory. Keep in mind that you should not make any changes to that file as it might be overwritten during fail2ban upgrade.