My ten-year-old son wanted a Minecraft server for playing online with friends. I wanted something small, controlled, allowlisted, and useful as a real-world excuse to run rootless Podman with systemd on an Oracle OCI Free Tier ARM instance.
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Cloud, databases, networking, and ham radio
Welcome to my personal technology blog.
I write about the systems I build, break, fix and occasionally understand on the first attempt. My topics range from Oracle Cloud Infrastructure and database platforms to networking, IPv6, OpenWrt and home automation.
You will find practical notes about cloud architecture, high availability, Oracle Multicloud, connectivity, routing and database migrations. I focus on real configurations, useful commands, troubleshooting and the lessons hidden inside failed experiments.
Networking gets a lot of attention here. I explore IPv6, WireGuard, VPNs, OSPF, BGP, firewalling and routing between cloud environments and private networks.
Several articles describe how I connect Oracle Cloud with my home network. Others cover CGNAT, public IPv6 access, OpenWrt routers and segmented networks.
My home network serves as a permanent technology lab. It includes VLANs, DNS, firewall policies, secure access, wireless networks and family-friendly device separation. It also provides a reliable environment for testing ideas before they reach production. Sometimes the test works immediately. More often, a packet takes an unexpected route and starts a new investigation.
Ham radio and HAMNET form another part of the blog. I write about antennas, digital modes, radio networking and the technical links between computers and radio systems.
The articles reflect my own practical experience. I document working solutions, failed attempts, strange behaviour and the configuration changes that finally make things work.
Expect technical details, command-line examples and honest lessons from real projects. This blog is for engineers, administrators, technology enthusiasts and anyone who enjoys finding out why a system behaves the way it does.
Disclaimer
All content published on this blog represents my personal opinions, experiences and views. It is provided for informational purposes only and does not represent the official position, opinion or recommendations of my employer or any affiliated organization.
The content does not constitute an official statement, endorsement or commitment by my employer. Examples, technical recommendations and opinions are based on my personal experience and should be evaluated independently.
- Minecraft Server on OCI Free Tier with Rootless Podman
My ten-year-old son wanted a Minecraft server for playing online with friends. I wanted something small, controlled, allowlisted, and useful as a real-world excuse to run rootless Podman with systemd on an Oracle OCI Free Tier ARM instance. - IPv4-to-IPv6 Relay for Home Services Behind CGNAT
My home network has public IPv6 but no public IPv4 because of CGNAT. This article describes how I use a small Oracle Cloud Free Tier Ubuntu VM, systemd and socat to relay public IPv4 SSH and WireGuard traffic into IPv6-reachable home systems. - OpenWrt: Accessing HAMNET over L2TP
Anleitung zur Einrichtung eines L2TP-Zugangs ins HAMNET auf einem OpenWrt-Router, inklusive Firewall, Routing, DNSMASQ und Troubleshooting. - Connect Your Home Office to Oracle Cloud – DOAG 2024
On Tuesday, November 19, 2024, I had the opportunity to speak about Oracle Cloud. Have you ever wondered how to connect your home office to the Oracle Cloud and exchange routes dynamically with BGP? - Install OPNsense® on Oracle Cloud Infrastructure (OCI)
Easily install OPNsense® on Oracle Cloud Infrastructure (OCI) to secure your cloud environment with a community-driven firewall solution. - Install OpenWrt on TP-Link EAP245 v1
How-to install OpenWrt on TP-Link EAP245 v1 - Interview: Oracle 11gR2 nach 19c migrieren
Interview: Migration von 11.2 auf 19c – von Single Instance zur CDB/PDB - WireGuard VPN over IPv6 with OSPF on OCI – Part IV
This post will describe the way to setup a WireGuard site-to-site VPN using IPv6 and OSPF in the Oracle Cloud Free Tier. Part IV is focused on routing and OSPF. - WireGuard VPN over IPv6 with OSPF on OCI – Part III
This post will describe the way to setup a WireGuard site-to-site VPN using IPv6 and OSPF in the Oracle Cloud Free Tier. Part III is focused on the WireGuard setup and configuration of the home router. In my case it’s an EdgeRouter™-X with version 2.0.9. - WireGuard VPN over IPv6 with OSPF on OCI – Part II
This post will describe the way to setup a WireGuard site-to-site VPN using IPv6 and OSPF in the Oracle Cloud Free Tier. Part II is focused on WireGuard setup and configuration in the cloud. - How to remove the Google DNS server entry from a Kindle?
How to remove the Google DNS server from my Kindle? Configuring my Kindle network configuration, I observed something spooky. Despite using DHCP and my own network services, there appeared the Google DNS server address 8.8.8.8 in the network configuration, always. - Oracle 19.12 EMON large consumption of PGA memory
How to troubleshoot excessive PGA memory usage by Oracle 19.12 EMON/Q processes after the July 2021 RU, including AQ queue checks and the DBMS_AQADM workaround. - WireGuard VPN over IPv6 with OSPF on OCI – Part I
This post will describe the way to setup a WireGuard site-to-site VPN using IPv6 and OSPF in the Oracle Cloud Free Tier - It’s not me, it’s you! … Me? No! It’s you! – black hole/null routing
A practical explanation of blackhole/null routing for home networks, showing how a core router can drop unused private IPv4 destinations locally instead of forwarding them to the default gateway. - Delete IPv6 Route on EdgeRouter-X
How to remove a stale IPv6 static route from an EdgeRouter-X when it has disappeared from the saved configuration but still exists in the Quagga/Zebra routing table. - DOAG-Studio-Interview mit Bruce Momjian
DOAG-Studio-Interview mit Bruce Momjian über PostgreSQL, Open Source, internationale Community und den Einstieg in die Mitarbeit am Projekt. - Disconnect Oracle Database Sessions with srvctl and DBMS_SERVICE
How to disconnect long-running Oracle database sessions during RAC maintenance using srvctl stop service and DBMS_SERVICE.DISCONNECT_SESSION. - Oracle Real Application Cluster: Connecting and using RAC
Eine wiederveröffentlichte DOAG-2013-Präsentation über Oracle RAC, Load Balancing, Failover und die richtige Nutzung von RAC-Verbindungsmechanismen auf Anwendungsebene.