Tag: sysadmin

Self-hosted email with Mailcow or Stalwart means daily SPF, DKIM, DMARC, and IP blacklist battles. Here's the honest case against running your own mail server.

Set, verify, and sync your timezone in Ubuntu using timedatectl — one command to fix the clock on a newly provisioned server.

socat wires TCP, UDP, Unix sockets, files, and serial ports together. Port forwarding, OpenSSL tunnels, traffic capture — this is netcat with superpowers.

ss replaces netstat on modern Linux: faster, shows more socket detail, and reads from the kernel. Every netstat command you rely on, rewritten for ss.

Generate SSH keys, set up passwordless auth, configure SSH, and transfer files securely with SCP — the foundation of headless Linux work.

The Ubuntu HWE kernel brings newer hardware support to LTS releases — how to switch from generic to HWE and what you gain.

What is lost+found and why does it exist? fsck puts recovered file fragments there after a crash — and no, you can't delete it.

Packages have been kept back during apt upgrade — what it means, why it happens, and how to safely install or hold those packages.

Update one package with apt without upgrading everything else — the exact flag, version pinning, held package handling, and the apt vs apt-get distinction that trips people up.

PID 1 zombie reaping in containers — tini, dumb-init, and docker --init compared; when each one fixes your signal handling and stops your 10s shutdown tax.

Your RAID 5 rebuild on a modern multi-TB drive has a 40-50% chance of hitting a URE before it finishes. Here's the 2026 math and what to do about it.

You've been compromised. Now what? A practical incident response playbook for self-hosters who didn't think they'd need one until right now.