Jan-Piet Mens.

Jan-Piet's mug I am a systems architect and consultant and sometimes available for hire. I am fluent in several programming languages and in four natural languages: English, Spanish, German and French. I'm proficient with all things Unix and Linux, and I'm particularly efficient when given the task of getting things to work for you.

I blog and tweet as @jpmens.

Areas of work

I play tricks with DNS and have authored Alternative DNS Servers, a 700 page book on Open Source DNS servers. I integrate Mail Transport Agents with LDAP directory services and make the two sing. I've done a lot of nitty-gritty with IBM/Lotus Domino (with the C API and a bit of Lotusscript) such as creating automatic user creation server-tasks. I'm very good at getting data in and out of systems, and I've built Public Key Infrastructure (PKI) systems with OpenSSL as well as setting up large Bacula backup installations.

I have successfully completed a large number of interesting projects; have a look at my profile.


In the course of the last years I've written large amounts of text, but most of it was for my clients and has probably long been recycled or is otherwise unretrievable from old punch cards, magnetic tapes or any other data carrier. Of the public documents, this lists some of the notable exceptions:

Süßes oder Saures: Rechner überwachen mit samhain
an introduction to the samhain file integrity checking system
Jan-Piet Mens; iX 8/2010, S. 127
Selbstporträt; NanoBSD: FreeBSD für Embedded-Systeme erstellen
an article which describes creating NanoBSD images for embedded systems.
Jan-Piet Mens; Selbstporträt; NanoBSD: FreeBSD für Embedded-Systeme erstellen; iX 5/2010, S. 146
Graf Backup; Version 3 der Backup-Suite Bacula
new features in Bacula version 3.
Jan-Piet Mens; Graf Backup; Version 3 der Backup-Suite Bacula; iX 6/2009, S. 70
Alternative DNS Servers
A 700+ page book discussing Choice and Deployment, and Optional SQL/LDAP Back-Ends in sundry Open Source DNS servers.
Jan-Piet Mens; Alternative DNS Servers; UIT Cambridge, 2009
Rückversicherung, Open-Source-Backup-Software im Vergleich
a description of three Open Source backup programs: Bacula, Amanda and BackupPC
Jan-Piet Mens; Rückversicherung, Open-Source-Backup-Software im Vergleich; iX 9/2007, S. 54
Schwarze Löcher, Realtime Blackhole Lists auf DNS-Basis
this article describes the fight against Spam with DNS Black Lists and rbldns, as well as integration with the NixSPAM lists which are managed by the iX magazine.
Jan-Piet Mens; Schwarze Löcher, Realtime Blackhole Lists auf DNS-Basis; iX 7/2004, S. 124
Maschinen im Verzeichnis - DNS in LDAP
where I describe, in German, a select number of tools with which DNS data can be stored, managed and retrieved from a DNS server which feeds from and LDAP directory server. PowerDNS and ldapdns are two programs which are discussed.
Jan-Piet Mens; DNS in LDAP; freeX 1/2004, S.16
LDAP ruft Lotus Domino
This article in German describes the possibilities that an administrator has when accessing a Domino Directory via LDAP and what advantages a Unix administrator has with that combination. Topics include setup, Directory Assistance, Mail clients such as Pine, and directory manipulation.
Jan-Piet Mens; LDAP ruft Lotus Domino; freeX 5/2003, S.16
Notes/Domino Integration Using Lightweight Clients
In this article I describe how to retrieve data from Lotus Notes/Domino databases via HTTP and other methods to integrate foreign Domino servers and Notes applications with Unix/Linux environments in which no Domino exists.
Jan-Piet Mens; Notes/Domino Integration Using Lightweight Clients; The View September/October 2003, p. 43
Ohne Schnörkel, Das Web auf der Kommandozeile mit curl
describes some of the possibilities in using the command-line cURL by Daniel Stenberg and installation as well as some examples in using the excellent libCurl library on Unix/Linux and Windows systems. In the German language.
Jan-Piet Mens; Ohne Schnörkel, Das Web auf der Kommandozeile mit curl; iX 8/2003, S. 128
Pound is a reverse proxy and load-balancer which is easy to set up and very powerful. This review in German, points out some of Pound's strengths.
Jan-Piet Mens; Pfundsache; Umgekehrter Proxy mit Lastverteilung: Pound; iX 5/2003, S.82
This long article in German, describes integration of LDAP with newer versions of the sendmail MTA, detailing building, configuration as well as usage of this powerful program.
Jan-Piet Mens; Oberpostdirektor; Sendmail mit OpenLDAP verwalten; iX 1/2003, S. 134
TCP/IP over ISDN. Frequently Asked Questions
This (very old) document describes methods which can be used to run TCP/IP and related protocols over ISDN networks. Most of the software and procedures described herein have only been tested on German 1TR6 or Euro ISDN (DSS1) networks. It had a monthly posting to the newsgroups: de.comm.isdn, de.comm.internet, de.answers, news.answers and was last updated in June 1996
Jan-Piet Mens; TCP/IP over ISDN FAQ; www.faqs.org/faqs/de-isdn/tcp-ip/; June 1996
Patchup: Benutzerorientierte Shellvariablen
Jan-Piet Mens, iX-Archiv, 10/1994, Seite 204


I've recently held the following talks at conferences:

Exim and LDAP -- Making Exim talk to an LDAP directory server
The Exim Mail Transfer Agent contains support for querying information from LDAP directory servers. After a short refresher on LDAP and Exim's configuration, this talk will show you real-world examples of how to route e-mail depending on information gleaned from LDAP. We discuss virtual hosting, conditional routing, SMTP authentication, and adding your own attributes and object classes to configure Exim for particular tasks. We also show you how easy it is to add e-mail routing for your choice Groupware system. Held at the UKUUG Summer 2009 conference in Birmingham.
The Perdition and NGINX IMAP Proxies
The Perdition and nginx (Engine X) IMAP/POP-3 proxies enable clients to be directed to arbitrary back-end IMAP/POP-3 servers depending on the result of a database lookup. We discuss why you would want to implement such a proxy, what these tools can do for you, and show you how to configure the tools to suit a variety of situations. Held at the UKUUG Spring 2010 conference in Manchester.
A bird's-eye view on DNSSEC
It's inconceivable you don't know what DNS is, but do you know what DNSSEC is? As a UNIX/Linux admin you'd better. DNSSEC signs DNS replies and gives users a warm fuzzy feeling that all is well, but is it really? What is DNSSEC, and what problems does it solve? What is signing, which components are involved, what can go wrong? How do you detect that DNSSEC is working, and what can an experienced user do to prove it isn't? Held at the UKUUG Spring 2011 conference in Leeds, and at LOAD Days in April 2011.
Unbound as a caching validating DNSSEC resolver
You've heard of DNSSEC and want to install a validating DNSSEC caching server on your workstation to experience DNSSEC? We suggest you use Unbound -- a validating, recursive, and caching DNS resolver with some tricks up its sleeve.We'll show you how to configure Unbound to use it as a caching server on yourworkstation (yes, Windows also), ensure DNSSEC-validation is being performed, add DLV and tweak it to serve you some local DNS data. Held at the UKUUG Spring 2011 conference in Leeds, and at LOAD Days in April 2011.
DNSSEC zone-signing tool chest
DNSSEC key-management and zone-signing can be, but must not be, a pain. In forty-five minutes we give you an overview of utilities you can use to create keys and sign zones. Whether you prefer seeing rather than believing or want everything to be as automatic as possible, one of these tools will satisfy your signing needs. We'll discuss BIND's utilities, BIND's auto-signing, DNSSEC-tools, Zone Key Tool (ZKT), OpenDNSSEC, and PowerDNSSEC. Held at the UKUUG Spring 2011 conference in Leeds.


If you see me at a conference, I'd be glad if you talked to me. Otherwise, use e-mail. I prefer e-mail, but you can chat to me or phone.

E-mail:jp () mens.de
Voice:+49 171 8033011


Inhaltlich Verantwortlicher gemaess § 10 Absatz 3 MDStV: Jan-Piet Mens, Walther-Rathenau-Str. 36, 33602 Bielefeld, 0171 8033011.

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