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In the previous post, we described how to install Fail2ban to protect your system. Now we are going to go a step further to activate the reporting of malicious activity to global blacklist managed by the tool AbuseIPDB. What is AbuseIPDB? AbuseIPDB is a project dedicated to helping systems administrators and webmasters check and report IP addresses which are involved in malicious activities such as spamming, hacking attempts, DDoS attacks, or any abusive activity on the Internet. ...

What is Fail2ban? Fail2ban is a software written in Python which help us to prevent brute force or DDoS attacks. It uses the failed access attempts logged in the system to detect the malicious IP addresses. Then, these IP addresses are blocked to avoid more attempts. It’s a software highly recommended to have installed in any system exposed to The Internet. How does Fail2ban work? Fail2ban is as a daemon which is monitoring every access to the system to the different services which have open ports (Mainly SSH, HTTPS…). It monitors the number of access attemps from a single IP address, and when Fail2ban detects the number of attemps which are suspicios to be an attack. Once identified a possible attacker Fail2ban uses the system Firewall (Iptables in Linux systesms) to block the IP address. From that moment that IP address will not be allowed to access the system. ...

First off, as a prerequisite it is needed to have a CLI access to the Debian OS. It can be done using a keyboard and a screen connected to the Raspberry Pi, or using a SSH connection. If you have followed the post of how to install Debian On a Raspberry Pi 4, you should be able to access with SSH using the Ethernet (RJ45) port. Also, you should have the SSID and the password of your Wi-Fi connection, and it should be enabled the DHCP protocol in your router. ...

I have several Raspberry Pi and in all of them I have used the Ubuntu distro. However I also wanted to use Debian as it is one of the most used Linux distros. Besides Ubuntu is based on Debian, so I guess I will feel confortable with it. Debian vs Ubuntu Debian is more stable than Ubuntu, indeed, it is one of the most stable Linux. The releases in Debian are not as frequent as in Ubuntu, and the software updates in Debian usually don’t have the latest versions. Besides, Debian is lighter because the software it has is the basic one. ...

iPerf is a tool designed to test the bandwidth between two hosts using the network. It is a really simple, powerful CLI which allows generating traffic / load TCP or UDP between 2 hosts. You could use to measure the maximum bandwidth of the network between a client and a server. It can be used to do stress tests of the Ethernet, Wi-Fi or of your ISP. iPerf2 vs iPerf3, what is the difference? There has been different versions of this tool in the last years. It started ttcp from the National Laboratory for Applied Network Research (NLANR), and then it was developed iPerf (iPerf 2). iPerf3 is a new implementation from scratch, with the goal of a smaller, simpler code base, and a library version of the functionality that can be used in other programs. The functionality between iPerf2 and iPerf3 are mostly compatible, however you should know they use different ports by default. In iPerf2, the default port is 5001, and in iPerf3, 5201. ...

Some people are interested in have a private server in order to play CS GO (Counter-Strike: Global Offensive) with their friends. The process is easy to follow. What is needed? A server Memory: At least 2GB RAM (I recommend 4GB) Disk: At least 15 GB os disk space CPU architecture: x86 (ARM not supported) A Valve account Create a new user First of all, it is important to create a new user in Linux in order to prevent CS GO server possible hacking to affect your Linux node. ...

I have faced an issue in a web server using NGINX while trying to upload a file using wordpress. In the nginx error log I saw the error “Client intended to send too large body” in this entry: $ tail -f /var/log/nginx/*error*.log 2020/09/01 14:31:04 [error] 884#884: *126565 client intended to send too large body: 1195619 bytes, client: 55.173.250.46, server: test.com, request: "POST /wp-json/wp/v2/media?_locale=user HTTP/2.0", host: "test.com", referrer: "https://test.com/wp-admin/post.php?post=2460&action=edit" ...