Tutorials

You’re visiting a site — or running one — and instead of content, the browser returns a bare error page with no explanation. HTTP error 431 is one of the quieter HTTP status codes, but it has a clear cause and a short list of fixes. Unlike server-side 5xx errors, 431 is a client-side response. […]

What Is ERR_NAME_NOT_RESOLVED? Type a URL, hit Enter, and instead of a page you get net::err_name_not_resolved. The browser couldn’t translate the domain name into an IP address. That translation is DNS — Domain Name System — and something broke in that chain. The process works like this: your browser asks a DNS resolver for the

Your browser hit the redirect limit. It tried 10, maybe 20 times to load your WordPress site and kept getting bounced between two URLs with no exit. Now you’re looking at ERR_TOO_MANY_REDIRECTS and your site is completely inaccessible. This error almost always comes from a misconfiguration, not a hack or mysterious server fault. The seven

Every bot on the internet knows that SSH lives on port 22. It’s the first door they knock on. Within minutes of spinning up a fresh Linux server, you’ll see login attempts from IPs you’ve never heard of, hammering away at the default SSH port number with dictionary attacks. The logs fill up fast. Changing

Your web application just went from 200ms response time to 14 seconds. Users are bouncing. Revenue is bleeding. And you’re staring at server logs that tell you absolutely nothing useful. This is exactly the kind of problem New Relic was built to solve. It’s a full-stack monitoring tool that tracks application performance, infrastructure health, browser

Every Linux process inherits a set of environment variables from its parent. These key-value pairs control how shells behave, where programs look for executables, and which configuration a running application picks up. Get them wrong and your deployment breaks at 2 AM. Get them right and you’ve got a clean, portable system config that travels

You’ve got a backup script. It works when you run it by hand. Now you need it to run at 2 AM every night without you babysitting the terminal. That’s where cron comes in, and getting the crontab syntax right is the difference between a script that fires on schedule and one that silently does

You’ve downloaded a .zip file to your server. Now what? On most Linux systems, double-clicking isn’t an option. The unzip command is how you crack open zip archives from the terminal, and unlike tar or gzip, it doesn’t come pre-installed on every distro. That distinction matters. Plenty of sysadmins SSH into a fresh VPS, type

Every sysadmin hits the same wall eventually: you’ve got 400 config files, one wrong IP address in all of them, and exactly zero interest in opening each one by hand. That’s where the sed command earns its keep. The Linux sed command (short for stream editor) lets you find, replace, insert, and delete text in

You click on a site and get a white page with “Error 522: Connection timed out.” Your origin server is alive, your code hasn’t changed, and nothing in your deploy pipeline looks wrong. Yet Cloudflare insists it can’t reach your box. Error 522 is an HTTP status code specific to Cloudflare. It fires when Cloudflare’s

You click a link. Chrome throws ERR_CONNECTION_RESET at your face. No page, no data, just a terse error code on a white screen. The browser tried to talk to the server, the server hung up mid-sentence, and now you’re stuck. This err_connection_reset error means the TCP connection between your browser and the remote server was

Your site’s down. Server’s fine. Hosting account is active. Nothing in the error logs. Nine times out of ten, a misconfigured DNS A record is the culprit. This guide covers checking your A record, verifying it matches your hosting IP, and fixing domain pointing when things break. What Is a DNS A Record A DNS