Chris A. Brandlehner BLOG

Smarte Pumpenpflege mit dem Shelly – Stillstand vermeiden und Heizungssteuerung respektieren

Christian Brandlehner — Wed, 1 Oct 2025 14:47:55 +0200

Viele Heizungsanlagen besitzen Umwälzpumpen, die außerhalb der Heizsaison oft über Monate hinweg stillstehen. Dieses lange Stillstehen kann zum Problem werden: Rotoren verkleben, Lager setzen sich fest und die Pumpe läuft bei Beginn der Heizsaison nicht mehr zuverlässig an.

CrowdSec auf der E.F.A. — Erfahrungen, Zertifizierungen und eigene Szenarien

Christian Brandlehner — Mon, 29 Sep 2025 19:26:26 +0200

In diesem Beitrag beschreibe ich kurz, was CrowdSec ist, welche Zertifizierungen ich abgeschlossen habe, wie ich CrowdSec auf der E.F.A. (Email Filter Appliance) integriert habe, welche Filter out-of-the-box funktionieren — und wie ich fehlende Unterstützung (z. B. für MailScanner) durch eigene Parser und Szenarios ergänze.

Was ist CrowdSec?

CrowdSec ist eine Open-Source-Plattform zur Erkennung und Abwehr von bösartigen Aktivitäten anhand von Log-Analysen. Der Kern besteht aus einem lokalen Agenten, der Logs einliest, Ereignisse korreliert und auf Basis von Signalen (sogenannte scenarios) Entscheidungen trifft. Erkenntnisse können lokal genutzt oder an die Community-Sharing-Plattform gesendet werden, um die Reputationen von IPs zu teilen.

Meine Zertifizierungen

Ich habe mehrere Zertifizierungen rund um CrowdSec durchlaufen, die mir geholfen haben:

Verständnis der Architektur (agent, bouncer, hub)
Erstellung eigener Parser und Szenarios
Integration mit externen Diensten (z. B. Firewalls, API-basierte Bouncer)

Visualized SSH login failures

Christian Brandlehner — Thu, 27 Jan 2022 17:53:57 +0200

When running a Linux server, which is accessible from the Internet, you will see a lot of failed SSH authentication attemtps.
This article is not about securing your server (ssh-port-change, fail2ban, private/public-key-auth only, ...) but about visualizing these attacks.

ISC BIND - enabling query statistics on CentOS

Christian Brandlehner — Fri, 21 Jan 2022 10:03:17 +0200

ISC BIND allows for export of statistics using a web UI. This artice can help you avoid a common pitfall on CentOS.

VMware ESXi mount a NFS share on a Synology Diskstation

Christian Brandlehner — Sun, 2 Jan 2022 14:43:43 +0200

Mounting a NFS share should be an easy task, however you might fail to mount the NFS share.
The ESXi vmkernel.log might show this error:
WARNING: NFS41: NFS41ExidNFSProcess:2054: Server doesn't support the NFS 4.1 protocol

How to recover a lost certifier file

Wed, 15 Jan 2020 12:52:33 +0200

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Installing HomeBridge as Docker Image on Synology

Mon, 8 Feb 2016 20:29:29 +0200

This article explains how to install and omeBridge, an opensource implementation of Apples HomeKit API, on a Synology Diskstation.
This tutorial requires that you own a Synology Diskstation with an Intel CPU that can run Docker.

Fun with Eclipse Browser Settings in IBM Notes

Thu, 26 Dec 2013 13:30:59 +0200

Just because we can, you can play around with some settings in IBM Notes on Windows.

Instead of using the Internet Explorer engine to render websites in Notes you can use XULrunner, the engine from the popular Firefox browser.

First check which engine Notes is currently using by opening a browser window within Notes (Open - Web), you may have to check your preferences to use the internal browser.
Go to https://www.whatismybrowser.com/

Now edit the file [notesprogramdir]/framework/rcp/plugin_customization.ini and add the two lines:
com.ibm.rcp.ui.browser/embeddedBrowser=Mozilla
com.ibm.rcp.rte/RTEBasedBrowser=XULRunner

Now close all browser windows and restart Notes.

Annoying Scroll-Lock indicator popup on Lenovo Thinkpad with Windows 7

Wed, 25 Aug 2010 08:22:29 +0200

On a Lenovo ThinkPad W510 I had an annoying problem with a popup indicating if the Scoll-Lock key was pressed. That tiny little grey window was popping up in the lower right corner of the screen.
The reason for hating that popus is that in Flightsimulator X the Scroll-Lock key is used to open the ATC window. If you play in DirectX fullscreen mode the screen flickers heavily for several seconds.
I found that the indator is not a Thinkpad feature but part of the Widcomm Bluetooth Stack. No idea why that software is doing this kind of stuff but here is the trick how to disable that indicator popup:
Use your registry editor and change the DWORD for KeyIndication in HKEY_LOCAL_MACHINE\SOFTWARE\Widcomm\BTConfig\General to a value 0. To reenable restore the default value of 1.

Is reading MIME emails slow in Lotus Notes 8.x after upgrading to Internet Explorer 8? (Solution inside)

Mon, 8 Jun 2009 13:19:51 +0200

I installed Internet Explorer 8 some days ago and wondered why the integrated Webbrowser now takes very long to start and why opening a MIME email takes more than a minute.