If your Raspberry Pi is open to the internet or even on a large network, basics security tips about SSH are not always enough to prevent attacks. Fail2ban can help you to detect excessive login attempts and block corresponding IP addresses. By default, it's enabled as soon as you install Fail2ban.
If you followed the tutorial, "How to Install and Configure fail2ban on Ubuntu 10.04 for SSH and Pure-FTPd" then you should have Fail2ban installed and configured for SSH and Pure-FTPd.You may be curious how to view which IP's are banned or blocked by Fail2ban, or you may wan't to remove some of them from the banned list.
For example, if you set the usedns setting to no, Fail2ban does not use reverse DNS to set its bans, and instead bans the IP address.When set as warn, Fail2ban performs a reverse lookup of the hostname and uses it to perform a ban.. The chain setting refers to the series of iptables rules where jumps should be added in ban-actions. By default, this is set to the INPUT chain.
Below we will configure Fail2ban to easily prevent an sasl brute force attack by blocking the offending IP address after a set number of invalid login attempts. For the purpose of this article, we will be using MailCleaner 2018.02 based on Debian 8 although this method also works on MailCleaner 2017.08. First you will need to install the ...
Thank you so much for replying, i have attached the jail.conf file from my server, the thing is, iget the email notifications, but the IP is not blocked, it seems like fail2ban is just not communicating with iptables, or something ;) I changed the email address below just to avoid any spam bots from sending me loads of rubbish.
Right now, we have entered the Localhost IP addresses in IPv4 and IPv6 formats. It means that Fail2Ban will not ban the server itself from logging in. bantime: This is the time in seconds for which the blocked IP address will not be able to login. Once the IP address is blocked, you cannot login again for 3600 seconds.
This is probably not the best approach. Finding IPs from your fail2ban and then just bulk blocking whole subnets is likely to catch a lot of ok traffic in the mix. Anyways, I'd use the /24. You want to do the smallest size possible so you don't spread your net too far. However, the /23 would encompass the /24 and another /24.
- Blocking is per IP and NOT per service, but ideal as action against bruteforcing hosts. Prerequisite: It is required the OIP configuration must be done before configuring Fail2Ban service.
In principle, Fail2Ban is capable to interact with iptables firewall to automatically block an IP address when the number of unsuccessful login attempts hits a given threshold or rules defined in this guide.
The first is that Fail2ban has no interaction with certain applications such as API and AGI. The second case is that this program does not support IPv6 and Fail2ban will not do anything if the malicious person uses this type of IP for brute-force attacks. But the third case is the main weakness.
Fail2ban is a popular intrusion detection system for Linux. It monitors log files to identify automated attacks and failed login attempts. Once it identifies the IP address responsible for the intrusion, Fail2ban immediately blocks that IP address. It is very useful in blocking brute force attacks. It is really easy to install and use Fail2ban.