Papers / HowTo


Sometimes you just need a tiny hint to solve your problem. Here the things we found out - in most cases the hard way...

Firewalls / Forensics

Port forwarding to systems behind un-forwardable routers/gateways
...from behind DS-Lite, enabling availability for IPv4-services on IPv6-only networks, from behind stubborn provider routers, or the like.

IPv6 tunnel calculators
Calculating between IPv4 and their 6to4 IPv6 addresses made easy.

Firewall-Types: stateful? inspection? proxy?
Here you'll get a brief overview over the different types of firewall architectures.

HowTo send CheckPoint FW1 logs to syslog
Checkpoint's Firewall-1 does not offer sending its logs to a standard syslog by default. Here is a way around it.

HashID - Identify Hash Types
This is a small one-page application (runs offline as HTML with simple, embedded javascript) to identify which type of hash the one is ou just found (based on c0re's python version).

HowTo mirror a partition or complete PC via network - binary 1:1 copy
Imagine you get the task to quickly set up a number of identical workstations regardless installed OS(es) or filesystems. Here's how to do with on-board tools.

HowTo duplicate a Linux-PC or Patition via network - fast
Imagine you get the task to quickly set up a number of hardware-wise identical workstations. Unfortunately time is running out, the PCs have different hard disks or filesystem types, or you want to keep the other individual partitions or have differing partition sizes on your target PC. Here's how to do with on-board tools.

Hosting / Mail Protection

HowTo run Greylisting (on Debian/GenToo) step-by-step
Greylisting ( is a (relatively) new, resource-preserving measure against SPAM and virus mails, raising the barrier quite a bit and reducing the unwanted data traffic by a few orders of magnitude.
This is a step-by-step guide.

Kaputte Mailprovider
(German language only)
Kommen meine Mails nicht auf der Mailingliste an - oder nicht bei allen? Das k├Ânnte an einem kaputten Mailprovider liegen...

Assorted Stuff

Boot from USB3
You finally have acquired a shiny new USB3 stick - and Linux is mulishly refusing to boot from it?
Da hat man nun einen neuen, schnellen USB3-Stick - und das Linux will davon nicht booten. Erst wenn man den in einen USB2-Port steckt funktioniert's.

Doppelte Buchführung / Double Ledger Accounting - American Journal
An "American Journal" implements double ledger accounting in one single sheet/book, where each column represets one account. Here I created a practical version which includes a balance sheet (Bilanz & Einnahmen-Ausgaben-Überschussrechnung).
While it is implemented as OpenOffice/LibreOffice spreadsheet it does not contain any macros or programming, just plain formulas and thus should be simple to convert to nearly any spreadsheet.
While it currently is geared towards German requirements it should be adaptable to any need.

Dan Wells' 7 Punkte Plotting Methode
Autor Dan Wells präsentierte eine Plotting-Methode für Stories. Hier ein kleines Spreadsheet zum Plotten...

Tea Timer (JavaScript)
A good tea needs 3 minutes to bew. Thus this simple timer.
Ein guter Tee braucht 3 Minuten zum Ziehen. Daher dieser simple Timer.

Product History
Sometimes products just seem to be somehow strangely familiar. Maybe it is because you worked with its predecessor under a different name or brand. Or it is based upon some well known software. Thus here a list of products and its predecessors.

HowTo check the serial number on a EURO note
Here's how to check the serial number on an EURO bank note, including an online JavaScript calculator.
(Check der Seriennummer für Euro-Banknoten)

HowTo read GET requests in JavaScript
You don't always need CGI or Apache-Modules (e.g. PHP) to evaluate forms and generate a new page. This is a generic example on how to do URL stuff in JavaScript.

Video Streaming - selfmade
Sometimes you just want to be in control of your very own video streaming service. If you know how, then you can reach a respectable number of viewers without having to go overboard with prerequisites. And here is how:

Archived Docs (no longer of much use)

HowTo run ClamAV Anti Virus on a low memory system
This recipe lost its edge when startup times slowed down too much.