How to Install Fail2Ban on CentOS 8
To install Fail2ban, The EPEL repository needs to be installed first.
sudo yum install epel-release
Note: It will prompt for several permission Press "y" and "Enter" to continue.
Next, install fail2ban package.
sudo yum install fail2ban
Note: This will prompt for several permissions, Press "y" and "Enter" to continue.
Set fail2ban to start on boot automatically,
sudo systemctl enable fail2ban
Configuring local file settings.
Jail.conf contains a section which Configuration settings can be done for the fail2ban, we are not going edit this file because package upgrade can overwrite this file.
Jail.local contains same section where jail.conf file contains and it can override this values.
/etc/fail2ban/jail.d/ can override both jails.local and jails.conf files
First we begin with the jail.local file.
Open the file for editing,
sudo vi /etc/fail2ban/jail.local
Add the following content,
[DEFAULT]
# Ban hosts for one hour:
bantime = 3600
# Override /etc/fail2ban/jail.d/00-firewalld.conf:
banaction = iptables-multiport
[sshd]
enabled = true
If server uses firewalld instead of iptables, simply comment the banaction line
Restarting the Fail2Ban service to load new settings.
sudo systemctl restart fail2ban
To check status
sudo fail2ban-client status
sample output:
Status
|- Number of jail: 1
`- Jail list: sshd
To view detailed information of sshd
sudo fail2ban-client status sshd
Modify the content of the file /etc/fail2ban/jail.local
sudo vi /etc/fail2ban/jail.local
Setting ban time
#ban time setting to 600sec
bantime = 600
Setting conditions to ban a client
findtime = 600
maxretry = 3
In this example, the client is blocked if he makes 3 unsuccessful login attempts with in 10 mins.
Set-up email notification
# repace your mail id to get alert
destemail = root@localhost
sendername = Fail2Ban@servername
mta = sendmail
To configure mail alerts, set the following parameters such as,
- destemail is the email receiver
- sendername is the sender of the email
- mta will be the mail service used to send the email
To check the details of banned IPs and number of login attempts,
sudo fail2ban-client status sshd
Sample Output:
[root@my ~]# fail2ban-client status sshd
Status for the jail: sshd
|- Filter
| |- Currently failed: 4
| |- Total failed: 31
| `- Journal matches: _SYSTEMD_UNIT=sshd.service + _COMM=sshd
`- Actions
|- Currently banned: 2
|- Total banned: 2
`- Banned IP list: 218.92.0.148 117.196.250.234
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