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Jasmin SMS Gateway: Install & Configure on Ubuntu
To set up Jasmin SMS gateway on Ubuntu, install RabbitMQ and Redis, add the Jasmin apt repo, start jasmind, then add an SMPP connector, user and route in jCli. Jasmin is the open-source SMPP gateway I have installed most often for clients, from small schools sending exam results to companies
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Could Not Get Lock /var/lib/dpkg/lock-frontend: Fix
"Could not get lock /var/lib/dpkg/lock-frontend" means another apt or dpkg process is running. Wait for it or stop it cleanly. Never just delete the lock file. You SSH into a fresh Ubuntu server, type sudo apt install nginx , and get E: Could not get lock /var/lib/dpkg/lock-frontend. It is held by
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Linux OOM Killer Killed Your App? Find and Fix It
If your app dies with no error, the Linux OOM killer probably ended it. Run journalctl -k | grep -i "killed process" to confirm, then add swap and cap memory. The symptom is confusing: the app stops, there's no stack trace, the app log just ends, and Nginx starts returning 502s. Often it happens at
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SSH Permission Denied (publickey)? How to Fix It
"Permission denied (publickey)" means SSH reached your server but it rejected your key. Run ssh -v to see which key was offered, then check authorized_keys. Getting locked out of your own server is stressful, especially when a site is down and you need to get in now. The good news: SSH errors are
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Linux Server Hacked? What to Do in the First Hour
If your Linux server is hacked, isolate it, snapshot it, find how the attacker got in, rotate every secret, then rebuild a fresh server from clean backups. The worst thing you can do with a hacked server is what most people try first: kill the strange process, delete the suspicious file, and carry
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Linux "No Space Left on Device": Find and Free Disk Space
"No space left on device" means a filesystem is out of blocks or inodes. Run df -h and df -i, find big folders with du, then clear logs, Docker and caches. A full disk is one of the most common reasons a server looks "broken". The symptoms rarely say "disk full": the database refuses writes, uploads
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Nginx 502 Bad Gateway: How to Find and Fix the Cause
A 502 Bad Gateway means Nginx couldn't get a valid response from your app. Check the Nginx error log: it names the cause, usually a crashed app or wrong port. A 502 is one of the most common server emergencies, and it's usually fixed in minutes once you look in the right place. The key thing to
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Docker Bypasses UFW on Ubuntu: Why and How to Fix It
Docker publishes container ports with its own iptables rules, which run before UFW's. Fix it by binding ports to 127.0.0.1 or filtering in DOCKER-USER. This one surprises almost everyone who runs Docker on a VPS. You set up UFW, allow only SSH, HTTP and HTTPS, run ufw status and feel safe. Then you
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Self-Host an LLM with Ollama on an Ubuntu VPS (2026)
To self-host an LLM on an Ubuntu VPS, install Ollama, keep it on 127.0.0.1, pull a model that fits your RAM and put Open WebUI behind Nginx with HTTPS. A private model is useful when you can't send customer data to an API, when you want a fixed monthly cost, or when you need an internal chat or
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Ubuntu 24.04 Server Hardening Checklist for 2026
Harden Ubuntu 24.04 with automatic security updates, SSH keys only, no root login, a UFW firewall, fail2ban, and offsite backups you have actually tested. A fresh VPS gets its first automated login attempts within minutes of going online. Bots scan the whole internet for open SSH ports, default
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OpenClaw on a VPS: Install and Secure It (2026 Guide)
OpenClaw is an open-source AI agent that acts for you from chat apps. Run it on its own VPS, keep the gateway on loopback, and reach it over SSH or Tailscale. When I first wrote about OpenClaw in February 2026, it was the most talked-about open-source project of the year: an assistant you message on
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Linux User Management Script: Add, Lock, Delete Users
This Bash script adds, locks, deletes and audits Linux users safely: strong hashing via chpasswd, a forced first-login password change and archived homes. I published a user management script here in 2024, and a lot of people copied it. Looking at it again with the eyes of someone who now audits
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