TOPIC / TAG
Notes in debian
6 articles
fail2ban for SSH on Debian 13
Install fail2ban on Debian 13, understand the sshd jail the package already enables, tune bans in a local override, and check, test, and undo bans safely.
ufw Without Locking Yourself Out
Set up ufw on a Debian or Ubuntu VPS with SSH allowed first, a timed rollback in case a rule is wrong, and a clear view of the Docker ports ufw cannot see.
Unattended Upgrades You Can Actually Check
Enable automatic security updates with unattended-upgrades on Debian and Ubuntu, see exactly what it will install, pick a reboot policy, and confirm it really ran.
Add a Swap File to a Small VPS
Check memory first, create a swap file that survives reboots, set vm.swappiness with a sysctl drop-in, and remove it cleanly if you change your mind.
Disabling IPv6 on a Linux Server, and When Not To
Decide whether disabling IPv6 actually solves your problem, then do it with a sysctl drop-in or the ipv6.disable=1 kernel parameter on Debian, Ubuntu, Rocky Linux, or AlmaLinux, verify the result, and roll it back.
The First Hour on a Fresh Debian or Ubuntu VPS
Set up a sudo user, SSH keys, an sshd drop-in that blocks password and root logins, a ufw firewall, and automatic security updates on a new Debian or Ubuntu server, checking each step as you go.