Guides tagged “linux”

Step-by-step MdmHost guides about linux, sorted A-Z.

280 guides · page 5 of 14

  • Fix 403 Forbidden in Nginx

    Nginx returns 403 Forbidden when it will not serve a file or folder. Work through the usual causes, from a missing index file to permissions, deny rules and SELinux.

    BeginnerLinux server5 min read

  • Fix 502 Bad Gateway in Nginx

    A 502 Bad Gateway means Nginx could not get a valid answer from PHP-FPM or your app. Read the error log, then check the backend service, socket path, permissions and ports.

    IntermediateLinux server5 min read

  • Fix 504 Gateway Timeout in Nginx

    A 504 Gateway Timeout means PHP or your app took longer to answer than Nginx was willing to wait. Find the slow request, raise the right timeouts consistently, and fix the root cause.

    IntermediateLinux server5 min read

  • Fix a Docker container that exits immediately

    Find out why a Docker container stops right after it starts. Read logs and exit codes, then fix missing environment variables, a wrong command, background processes and restart loops.

    BeginnerLinux server5 min read

  • Fix Apache failed to start (AH00072 port in use and config errors)

    When Apache will not start, run a config test, read journalctl, and fix the usual causes - AH00072 port already in use, syntax errors, missing certificates and the AH00558 ServerName warning.

    BeginnerLinux server5 min read

  • Fix Docker daemon not starting

    Docker service failed to start? Read the real error with journalctl, then fix an invalid daemon.json, conflicting options, storage driver and overlay errors, a full disk or iptables problems.

    IntermediateLinux server5 min read

  • Fix Nginx 404 errors with try_files for pretty URLs

    Pretty URLs return 404 on Nginx when nothing routes them to your app. Add the right try_files line for WordPress, Laravel or a single-page app, and avoid root and alias mistakes.

    BeginnerLinux server4 min read

  • Fix Nginx 413 Request Entity Too Large

    Nginx returns 413 Request Entity Too Large when an upload is bigger than client_max_body_size. Raise the limit for one site or the whole server, match PHP's limits, and test.

    BeginnerLinux server5 min read

  • Fix Nginx failed to start: address already in use

    Nginx will not start when another program already holds port 80 or 443. Find what is using the port with ss, stop or move it, fix duplicate listen lines, then start Nginx.

    BeginnerLinux server5 min read

  • Fix PHP "Allowed memory size exhausted" fatal error

    PHP stops a script when it tries to allocate more memory than memory_limit allows. Find the script that hit the limit, raise the limit in the right place, and fix the cause.

    IntermediateLinux server6 min read

  • Fix SSH "connection refused", "timed out" and "permission denied"

    Work out what each SSH error means, test the port from your computer, and use the control panel's browser console to fix the firewall, the SSH service or key permissions.

    IntermediateLinux server3 min read

  • Fix SSH "Too many authentication failures" when connecting

    Learn why SSH offers too many keys and gets rejected, and fix it with IdentitiesOnly, ssh-agent and a small SSH config entry.

    BeginnerLinux server6 min read

  • Free disk space with docker system prune

    Find out how much space Docker uses with docker system df, then safely prune unused images, build cache, stopped containers and volumes, and schedule a cleanup that never touches your data.

    BeginnerLinux server5 min read

  • Free up disk space on a Linux VPS

    Find what is using space, then safely clear package caches, systemd journal logs, old Docker data and large log files without breaking running services.

    BeginnerLinux server3 min read

  • Get help in Linux: man pages, --help and tldr

    Find out what any Linux command does without leaving the server, using --help, man pages, man sections, apropos for searching, and tldr for short practical examples.

    BeginnerLinux server5 min read

  • Git push-to-deploy with a bare repository and post-receive hook

    Set up a bare Git repository on your Linux VPS and a post-receive hook so that every push checks out your code into the live directory and restarts the service.

    IntermediateLinux server6 min read

  • Give a user sudo access to specific commands only

    Grant a Linux user root rights for a short list of commands, such as restarting one service, using Cmnd_Alias and full paths, and avoid the wildcard and shell-escape traps.

    AdvancedLinux server5 min read

  • Hide the Nginx version and harden the default config

    Make Nginx give away less and accept less. Hide the version number, drop requests for unknown hosts, block dotfiles, limit methods and body size, and tighten timeouts.

    BeginnerLinux server5 min read

  • Host a Minecraft Server with Docker Compose on a Linux VPS

    Run a Java Edition Minecraft server in Docker Compose on a Linux VPS, with a persistent world volume, memory limits, a whitelist and a plain backup routine.

    BeginnerLinux server5 min read

  • Host a Valheim Dedicated Server with Docker

    Run a Valheim dedicated server with Docker on a Linux VPS — compose file, UDP ports, persistent world data and safe updates.

    IntermediateLinux server6 min read

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