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MajorLinux 9c62e7f804 Logwatch fleet article: add cloud-image config-drift section 
Documents three more patterns surfaced in the 2026-05-10 fleet-mail
investigation, all hitting hosts derived from cloud images or
cross-provider migrations:

- Packer/snapshot-leftover myhostname (postfix EHLO + message-id
  identifies the build artifact, not the production hostname; remote
  spam scorers hate it)
- Empty relayhost silently routes mail via the public MX instead of
  the Tailscale-internal path, exposing it to spamchk that internal
  traffic bypasses
- Stale SASL passwd map referencing a missing file from a previous
  external-SMTP relay setup, deferring every send with "local data
  error"

Each looks benign in isolation. Together they made dcaprod's Logwatch
disappear into spamchk for weeks while showing 250 OK on the source.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-10 12:58:00 -04:00

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2026-04-06T09:52 2026-05-10T01:30

MajorLinux Tech Wiki — Index

A growing reference of Linux, self-hosting, open source, streaming, and troubleshooting guides. Written by MajorLinux. Used by MajorTwin.

Last updated: 2026-05-10 Article count: 111

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🐧 Linux & Sysadmin 01-linux/ 12
🏠 Self-Hosting & Homelab 02-selfhosting/ 39
🔓 Open Source Tools 03-opensource/ 10
🎙️ Streaming & Podcasting 04-streaming/ 2
🔧 General Troubleshooting 05-troubleshooting/ 48

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Recently Updated

Date Article Domain
2026-05-10 Logwatch Fleet Setup — Surviving Package Upgrades — added "Per-host config drift on cloud-image-derived servers" section: Packer-leftover myhostname, empty relayhost forcing public-MX path, stale SASL passwd maps from prior relays Self-Hosting
2026-05-10 Patching PHP 8.4 Implicit-Nullable Deprecations in Vendor Packages — generalized from a Castopod/UuidModel incident; covers the substring-match gotcha that turns a 30-second fix into a 30-minute one Troubleshooting
2026-05-10 Logwatch Fleet Setup — Surviving Package Upgrades — added Fedora CA bundle missing diagnosis, journald-vs-mail.log methodology note, and bounce-source-must-be-real-mailbox section Self-Hosting
2026-05-10 ClamAV Fleet Deployment with Ansible — added DigitalOcean monitoring caveat for 1vCPU droplets (with follow-up note: per-droplet relaxed alert can still trip; accept-the-page decision) Self-Hosting
2026-05-10 Claude Desktop MCP Mass-Disconnect After Blocking SSH Reboot Troubleshooting
2026-05-10 Castopod Posts Don't Appear on Mastodon — Diagnosing the Federation Path Troubleshooting
2026-05-08 Castopod: Stale Federated Avatar URLs After Remote Profile Updates Troubleshooting
2026-05-08 Tuning Netdata web_log_1m_successful for Redirect-Heavy WordPress Sites Troubleshooting
2026-05-07 Mastodon — The --prune-profiles Trap and How to Recover Self-Hosting
2026-05-02 WSL2 Backup via PowerShell Scheduled Task Linux
2026-05-02 SSH Config and Key Management Linux
2026-05-02 Wake-on-LAN via Router SSH Self-Hosting
2026-05-02 Tuning Netdata Docker Health Alarms to Prevent Update Flapping Self-Hosting
2026-05-02 ClamAV Fleet Deployment with Ansible Self-Hosting
2026-05-02 Fail2Ban Digest Mode — Fleet-Wide Quiet Alerts Self-Hosting
2026-05-02 Mastodon Instance Tuning Self-Hosting
2026-05-02 Ansible Check Mode False Positives in Verify/Assert Tasks Troubleshooting
2026-05-02 ISP SNI Filtering & Caddy Troubleshooting Troubleshooting
2026-05-02 Windows OpenSSH: WSL as Default Shell Breaks Remote Commands Troubleshooting
2026-05-02 Windows OpenSSH Server (sshd) Stops After Reboot Troubleshooting
2026-05-02 yt-dlp YouTube JS Challenge Fix (Fedora) Troubleshooting
2026-04-30 wp-fail2ban Plugin Logpath on Debian/Ubuntu (auth.log, not syslog) Self-Hosting
2026-04-30 LoRA adapter — GGUF conversion fails with 'config.json not found Troubleshooting
2026-04-29 iOS Tailscale Clients Report HostName="localhost" — Breaks /etc/hosts Generators Troubleshooting
2026-04-29 Python smtplib: Missing Date/Message-ID Headers Break Mail Clients Troubleshooting
2026-04-28 Ubuntu dist-upgrade Quarantines Third-Party Repos Troubleshooting
2026-04-26 Fantastical MCP Server: Permission Denied on Launch (macOS Quarantine) Troubleshooting
2026-04-25 rsync over Tailscale: Hung in TCP Teardown After Transfer Completes Troubleshooting
2026-04-25 Ollama: ollama run with Piped Stdin Bypasses Chat Template + SYSTEM Prompt Troubleshooting
2026-04-24 Fantastical Google Sync Error Flood — Phantom Calendars Fixed via syncselect Troubleshooting
2026-04-23 Pi-hole DoH / DoT Bypass Defense Self-Hosting
2026-04-22 Pi-hole v6 Adlist Management via SQL Self-Hosting
2026-04-22 Pi-hole v6 Group Management: Per-Client DNS Rules Self-Hosting
2026-04-22 Mastodon DB Maintenance — Statuses, Accounts, and VACUUM Self-Hosting
2026-04-22 Mastodon Federation — Domain Blocks, Silencing, and FediSeer Self-Hosting
2026-04-22 Pi-hole AI Blocklist Blocks Claude Desktop (ERR_CONNECTION_REFUSED) Troubleshooting
2026-04-21 Ansible Fails with Permission Denied While ssh <alias> Works (Host Alias Bypass) Troubleshooting
2026-04-20 Claude Code Remote Control — Mobile Access to a Persistent Host Session Self-Hosting
2026-04-19 AWS S3 Cost Management Self-Hosting

Writing Backlog

Topic Domain Priority From Gap?
Docker Compose networking deep dive Self-Hosting High No
Troubleshooting NVIDIA on Linux Troubleshooting Medium No
Pi-hole setup and local DNS Self-Hosting Medium No
Nextcloud setup with Docker Self-Hosting Medium No

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