Dovecot Mailarchiv

 Wed, 02 May 2018 19:13:45 +0200 
#^Mailquota-Management mit Dovecot
Ein ständig wachsender Datenbestand droht viele Mail-Infrastrukturen zu überfordern. Dabei gibt es zumindest für Dovecot einen Weg aus der Speicherfalle.

Für seine Nutzer gilt heute als selbstverständlich, dass das E-Mail-System durchgehend verfügbar ist und immer ausreichend Speicherkapazität zur Verfügung hat. Dennoch sind die Ressourcen natürlich endlich und kosten Geld. Daher kann ein schnell wachsender Datenbestand die Betriebssicherheit einer Mail-Infrastruktur durchaus gefährden. Das muss aber nicht sein.

#Dovecot #IMAP #Mailarchiv

such complex functions in IDaaS services?

 Wed, 14 Mar 2018 18:17:35 +0100 

#^IAM in the Cloud » ADMIN Magazine
Offers for identity management as a service (IDaaS) are entering the market and promising simplicity. However, many lack functionality, adaptability, and in-depth integration with existing systems. We look at how IT managers should consider IDaaS in their strategy.
Identity and access management (IAM) is a core IT discipline located between IT infrastructure, information security, and governance. For example, IAM tools help with the management of users and their access rights across systems and (cloud) services, to provide easy access to applications (preferably with a single sign-on experience), to handle strong authentication, and to protect shared user accounts.

#CIAM (Customer Identity and Access Management)


 Thu, 18 Jan 2018 18:52:14 +0100 
I already had a dockerized Selenium-Grid but it was a good idea to replace it with Selenoid. The state of automation and the video recording feature are really impressive.

Selenoid is a powerful implementation of Selenium hub using Docker containers to launch browsers.

Lightweight and Lightning Fast
Suitable for personal usage and in big clusters:
* Consumes 10 times less memory than Java-based Selenium server under the same load
* Small 7 Mb binary with no external dependencies (no need to install Java)
* Browser consumption API working out of the box
* Ability to send browser logs to centralized log storage (e.g. to the ELK-stack)
* Fully isolated and reproducible environment

#^Scalable Selenium Cluster: Up & Running | Ivan Krutov
by seleniumconf on YouTube

zu leichtfertig mit Zugangsdaten

 Thu, 09 Nov 2017 18:27:55 +0100 
#^Studie: DevOps-Teams gehen häufig leichtfertig mit Zugangsdaten um

In vielen Unternehmen mangelt es den DevOps-Abteilungen an Regeln für den sicheren Umgang mit privilegierten Accounts und Zugangsdaten – vielfach fehlt eine übergreifende Sicherheitsstrategie, wie CyberArks „Advanced Threat Landscape“-Report zeigt.

SMTP relay

 Fri, 13 Oct 2017 18:26:36 +0200 
So you can not send eMails from an M$ Azure VM? You need a SMTP relay outside of Azure?
Luckily Exchange Online Protection is an ideal solution you can directly sign up for. ;-) At least they know how to squeeze out their victims.

Icinga Director v1.4.0

 Tue, 10 Oct 2017 17:28:44 +0200 
#^Icinga Director v1.4.0 has been released
We tagged v1.3.2 more than two months ago and according our initial plans it should have been announced together with v1.4.0. However, sometimes things take longer than expected. But now it’s official: Director v1.4.0 is our shiny new release.

by zombies

 Mon, 09 Oct 2017 18:18:42 +0200 
#^Eliminating the zombie vulnerability – removing passive voice from the docs
If you can insert the words “by zombies” into a sentence, then that sentence very likely uses the passive voice. A colleague recently reminded me of this tip. It made me laugh, and so I thought it’s worth blogging about. If only to share the chuckle.

Here are some examples of zombie-infested sentences, and their equivalents using active voice.

Example 1
Geographic requests are indicated by zombies through use of the coordinates parameter, indicating the specific locations passed by zombies as latitude/longitude values.

Converting passive voice to active:
You can use the coordinates parameter to indicate geographic requests, passing the specific locations as latitude/longitude values.

For an even more concise effect, use the imperative:
Use the coordinates parameter to indicate geographic requests, passing the specific locations as latitude/longitude values.

#documentation #technical writing
 Mon, 02 Oct 2017 12:40:38 +0200 last edited: Mon, 02 Oct 2017 12:40:57 +0200  
#^Securing Network Time | Core Infrastructure Initiative
Date Published September 27, 2017
Since its inception the CII has considered network time, and implementations of the Network Time Protocol, to be “core infrastructure.” Correctly synchronising clocks is critical both to the smooth functioning of many services and to the effectiveness of numerous security protocols; as a result most computers run some sort of clock synchronization software and most of those computers implement either the Network Time Protocol (NTP, RFC 5905) or the closely related but slimmed down Simple Network Time Protocol (SNTP, RFC 4330).


 Tue, 26 Sep 2017 17:27:08 +0200 
Nice collection of #Jenkins pipeline examples.

pipeline-examples - A collection of examples, tips and tricks and snippets of scripting for the Jenkins Pipeline plugin

Was gibt es Neues vom Icinga Director?

 Tue, 01 Aug 2017 16:53:10 +0200 
ziemlich viel und es macht richtig Spass!

#^Was gibt’s Neues vom Director?
Gleich zwei neue Releases stehen an, und während die v1.3.2 bereits vor einer Woche inoffiziell getagged wurde, werden bei der v1.4.0 gerade noch die letzten Kanten rund geschliffen. Wenn nichts dazwischen kommt werden dann Anfang nächster Woche beide gemeinsam offiziell angekündigt werden.

Einfachere Suche, flexiblere Tabellen
Template Choices
Schnelleres Arbeiten mit einzelnen Services
Neue Dashboards und Dashlets
Vererbung ist alles
Genutzte Custom Variablen
VMware vSphere/ESXi Import
 Fri, 28 Jul 2017 16:55:16 +0200 
#^Securing Docker » ADMIN Magazine
Docker containers introduce serious security problems, but you can employ a number of methods to deploy them securely.

Few debate that the destiny of a hosting infrastructure is running applications across multiple containers. Containers are a genuinely fantastic, highly performant technology ideal for deploying software updates to applications. Whether you're working in an enterprise with a number of critical microservices, tightly coupled with a pipeline that continuously deploys your latest software, or you're running a single LEMP (Linux, Nginx, MySQL, PHP) website that sometimes needs to scale up for busy periods, containers can provide with relative ease the software dependencies you need across all stages of your development life cycle.

RDBMS containers

 Fri, 28 Jul 2017 13:04:28 +0200 last edited: Fri, 28 Jul 2017 16:55:45 +0200  
#^RDBMS Containers » ADMIN Magazine
If you spend very much of your time pushing containerized services from server to server, you might be asking yourself: Why not databases, as well? We describe the status quo for RDBMS containers.

Orpheus' Lyre

 Thu, 13 Jul 2017 16:11:58 +0200 
Was debugging some #Kerberos error messages in M$ Active Directory this morning. What a nice coincidence to find Orpheus' Lyre website just now.

#^Orpheus' Lyre

On Tuesday, 11 July 2017, at 1PM New York time, Microsoft, and various Linux distros and BSDs, released patches for Orpheus' Lyre.

We will be updating this blog post with more details as time passes. This vulnerability is quite serious, and we wish to give users a chance to apply patches before we discuss the full scope of the vulnerability. We urge users to apply and deploy patches forthwith and without delay.

In Greek mythology, Orpheus was a bard who put Cerberus to sleep with his music, and was then able to bypass Hades' guard. This vulnerability defeats Kerberos in a critical way permitting a bypass of mutual authentication. Thus we name it after Orpheus' Lyre much as Kerberos is named after Cerberus.

Its not actually a broken protocol, but it's all too easy to make subtle but disastrous implementation mistakes. Orpheus' Lyre is a serious vulnerability in some implementations of the Kerberos protocol.
MIT implemented it correctly, all others failed? Quite interesting. ;-)



 Fri, 07 Jul 2017 23:17:18 +0200 
There will be beta-exams for the new LPIC-OT at FrOSCon in August. Looking at the objectives for this new exam it contains a lot of what I have done recently.

#^DevOps Tools Engineer
DevOps is one of the most in-demand skills in open source today.  In order to meet this need with verified skills LPI, an established authority in Linux Administration, is developing the DevOps Tools Engineer certification.  These additional certified competencies strengthen the portfolio of today’s IT professionals.

As more and more companies introduce DevOps methodologies to their workflows; skills in using tools which support the collaboration model of DevOps become increasingly important. LPIC-OT DevOps Tools Engineers will be able to efficiently implement a workflow and to optimize their daily administration and development tasks.

This certification will be released in autumn 2017 and will test proficiency in the most relevant free and open source tools used to implement the DevOps collaboration model, like for example configuration automation or container virtualization.

The new certification is created according to LPI‘s community-based certification development process. This process relies heavily on involvement by the IT community.

A Step-By-Step Guide on How to Be a Little Evil

 Fri, 07 Jul 2017 18:21:53 +0200 
Nice introduction video for every M$ Windows user! But don't tell your domain adminstrators. ;-)

#^From User to Domain Admin: A Step-By-Step Guide on How to Be a Little Evil
by BeyondTrust on Vimeo

Let’s Encrypt limits

 Tue, 04 Jul 2017 14:37:53 +0200 

Let's Encrypt is now the largest certificate provider for internet facing servers (combining a Frost&Sullivan report on SSL/TLS certificates from 2016 and actual data from Let's Encrypt, LE currently issues around 80% of all browser-trusted certificates). It does not issue the "most secure" certificates (i.e., EV, or extended validation certificates, which require manual validation of the address and legal status of the web service owner), but its certificates provide a very good level of security for most of us.

When we started using Let's Encrypt (LE), we slowly learnt about various limitations imposed on users. There is not any single place where you can find all important information in one place so here's the first attempt. We will amend it as we learn more directly, or from your feedback.

Deep Dive into Capabilities

 Sun, 25 Jun 2017 22:57:10 +0200 
Secure Your Containers with this One Weird Trick
Did you know there is an option to drop Linux capabilities in Docker? Using the docker run --cap-drop option, you can lock down root in a container so that it has limited access within the container. Sadly, almost no one ever tightens the security on a container or anywhere else.

monitor the progress of data through a pipe

 Thu, 22 Jun 2017 23:48:49 +0200 
This is a really nice tool I didn't knew something like that exists. How many times I was wondering how the progress of loading a sqldump was.

man pv
pv shows the progress of data through a pipeline by giving information such as time elapsed, percentage completed (with progress bar), current throughput rate, total data transferred, and ETA.
To use it, insert it in a pipeline between two processes, with the appropriate options.  Its standard input will be passed through to its standard output and progress will be shown on standard error.


 Tue, 16 May 2017 15:01:11 +0200 
#^Understanding Firewalld in Multi-Zone Configurations | Linux Journal
Linux firewalls are handled by netfilter, which is a kernel-level framework. For more than a decade, iptables has provided the userland abstraction layer for netfilter. iptables subjects packets to a gauntlet of rules, and if the IP/port/protocol combination of the rule matches the packet, the rule is applied causing the packet to be accepted, rejected or dropped.

Firewalld is a newer userland abstraction layer for netfilter. Unfortunately, its power and flexibility are underappreciated due to a lack of documentation describing multi-zoned configurations. This article provides examples to remedy this situation.


 Fri, 03 Mar 2017 11:58:37 +0100 
#^How setting the TZ environment variable avoids thousands of system calls
TL;DR This blog post explains how setting an environment variable can save thousands(or in some cases, tens of thousands) of unnecessary system calls that can begenerated by glibc over small periods of time.This has been tested on Ubuntu Precise (12.04) and Ubuntu Xenial (16.04). Itlikely applies to other flavors of Linux, as well. It is very easy to test ifthis applies to you and to correct it, if so. Keep reading for more details!

To avoid extra system calls on server processes where you won’t be updating the timezone (or can restart processes when you do) simply set the TZ environment variable to :/etc/localtime (or some other timezone file of your choice) for a process. This will cause glibc to avoid making extra (and unnecessary) system calls.