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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 long does fail2ban ban?
10 minutes
For us, fail2ban uses iptables to ban the IP address of the offending system for a “bantime” of 600 seconds (10 minutes). You can, of course, change any of these settings to meet your needs. Ten minutes seems to be long enough to cause a bot or script to “move on” to less secure hosts.
How do I know if Fail2ban is running?
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 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.
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.
Is there a jail for failed ssh login?
There is only a single jail — sshd — which is responsible for monitoring SSH server logs for failed login event and setting firewall rules to block further attempts. Now we can check the statistics for sshd jail: As we can see, there were no failed logins so far. Now let’s try to log in several times with incorrect credentials.
How to unban an IP address on SSH?
You can also use Fail2Ban to manually ban or unban IP addresses for the SSH server. Use the command fail2ban-client set sshd banip 123.123.123.123 to ban an IP address and fail2ban-client set sshd unbanip 123.123.123.123 to unban it. Instead of “123.123.123.123” you need to specify the IP address you want to ban or unban.