Linux
Linux server guides from real setups: Ubuntu and Debian, systemd, firewalls, backups, mail and the gotchas that bite in production.
-
Brother Scan to SFTP: Receipts Straight Into a Hetzner Storage Box
A Brother MFC scans receipts via SFTP into a Storage Box sub-account. Port 22 vs 23, RFC4716 keys, reachability and the firmware update that fixed it.
Running Linux -
Server Migration: Build a Full Test Copy Before You Touch DNS
Moving a forum, WordPress, Nextcloud and mail off a dead Plesk box: pull with ssh -A, test via hosts file, doveadm imapc for mail, then the delta cutover.
Running Linux -
Domain Transfer Rejected: 2304 clientTransferProhibited Despite an AuthCode
Moving 19 domains off a closing reseller account: zone exports, AuthCodes, RDAP lock checks, a stdlib Python script and why an AuthCode is not an unlock.
Maintenance Linux -
The First Hour on a New VPS: IPv6, Reverse DNS and Port 25
Fresh Ubuntu 24.04 VPS: IPv6 that cloud-init didn't set, swap, SSH keys only, a provider mail block on port 25, PTR records, then KeyHelp on top.
Running Linux -
T-Online Rejects My Server: "554 Dialup/transient IP not allowed"
Gmail got my login codes in seconds, t-online.de refused the server. What Telekom checks, how I filed the unblock request and what the log showed.
Running Linux -
WordPress Moved Into a Subdirectory: 500 Error, Wrong URLs and an Admin User From SQL
Moved WordPress into /new/: fix RewriteBase, find a 500 with curl, set WP_HOME, rewrite links without breaking serialized data, add an admin via SQL.
Running Linux -
Website Cert Fine, Mail Cert Expired: Plesk's Stale Postfix SNI Map
Let's Encrypt renewed, web and IMAP fine, but SMTP still sent the expired cert. Plesk's Postfix SNI map was stale. How I found it and fixed it.
Maintenance Linux -
Daylight Saving Time on Servers: What Actually Breaks When the Clocks Change
Clocks went back tonight. What DST does to cron jobs, systemd timers, logs, databases, backups and game server restarts, and why my servers all run on UTC.
Running Linux -
Moving a Blog to a New Domain Without Losing Google: 301s, Canonicals, Search Console
How I moved my Ghost blog and main site to a new domain: 301 per path, Ghost url, canonicals, sitemap, Search Console Change of Address, IndexNow and Bing.
Running Linux -
New Mail Domain From Zero: SPF, DKIM and DMARC Passing on Day One
Setting up a brand-new mail domain on a self-hosted panel: DNS records in the right order, DKIM selector, Gmail "show original", alignment, PTR and HELO.
Running Linux -
Valid ZUGFeRD E-Invoices From Self-Hosted InvoicePlane in Docker
Monthly recurring invoices with InvoicePlane in Docker as valid ZUGFeRD 2.3 EN16931 PDF/A-3 files, checked with Mustang CLI. Patches and gotchas.
Running Linux -
Bots vs. Real Readers: Counting Blog Visitors From the Access Log
My blog logged 140 to 500 hits a day. Real readers: 15 to 61. The four filter rules I use on the access log, plus the small Python script and cron job.
Running Linux -
Hytale Server Without a Panel: Back to Plain systemd
My game panel died, so my Hytale server runs as a plain systemd service again. Unit file, FIFO console helper, backups and a log-tailing alert bot.
Running Hytale -
DMARC Reports Explained: What the rua XML Actually Tells You
What DMARC aggregate reports are, how to read the XML, the external rua authorization record most people miss, and when to move from p=none to reject.
Running Linux -
Moving Mailboxes Off a Shared Host: imapsync, DNS and the Outlook Autodiscover Trap
How I moved a small business mail domain to my own server: imapsync in Docker, delta syncs, MX/SPF/DKIM cutover, and why Outlook ignored my autoconfig.
Running Linux -
My Backups Were Silently Dead for 7 Weeks: How I Check Backup Freshness Now
Scheduled backups stopped in late August and nothing told me. The cleanup, the offsite fix, and a script that alerts when the newest backup is too old.
Running Linux -
Restoring a Site When the Files and the Database Are in Different Backups
Files in a dead server's full backup, the database only in a VM backup on offsite storage. How I found both, matched them and brought the shop back.
Running Linux -
Let's Encrypt Kept Failing After a Server Move. The Culprit Was a Second A Record.
Two A records after a migration meant round robin, and Let's Encrypt's multi-perspective validation kept hitting the old server. Diagnosis and fix.
Running Linux -
Mail + Web on One Server: 4 GB or 8 GB of RAM? I Measured It
Real RSS numbers from a panel box with mail and web: ClamAV eats over a gigabyte. Why summing ps lies, how to measure with smem, and when 4 GB is enough.
Running Linux -
Lower Your DNS TTL Before You Migrate a Server (A Checklist)
A 24-hour TTL turns a server move into a day of half-broken DNS. When to lower it, how to check what resolvers see with dig, and what to tell DNS support.
Running Linux