Guides
Ubuntu 24.04
Guides
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How to back up a Linux server
Dump the databases, copy the files to another machine every night with rsync and cron, and prove the backup works by restoring it.
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How to turn on automatic security updates
Have the server install security patches by itself every day, on Ubuntu with unattended-upgrades and on RHEL-based systems with dnf-automatic.
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How to set up a firewall on Linux
Block everything except SSH and the web with UFW on Ubuntu or firewalld on RHEL-based systems, without locking yourself out.
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How to get a free SSL certificate with Let’s Encrypt
Issue a trusted HTTPS certificate in one command with Certbot, redirect HTTP to HTTPS, and make sure it renews by itself.
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How to install Nginx on Ubuntu
Install Nginx, serve your first site from its own folder, and learn the three commands you will use every time you change its configuration.
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How to set up SSH keys
Replace passwords with a key pair, log in without typing a password, and then switch password login off for good.
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How to connect to a server with SSH
Open a secure command line on a remote server from Windows, macOS or Linux, and understand the host key prompt you see the first…
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How to flush your DNS cache
Make your computer forget old DNS answers after a site move or record change. Commands for Windows, macOS, Linux and every major browser.