Bejegyzések

Bejegyzések megjelenítése ebből a hónapból: június, 2014

Building a radiation detector from scratch 1 - the basics.

Before you begin If you follow this series of articles and maybe do some research on your own, you'll be able to build a simple radiation detection device and perform some simple, interesting experiments. I chose to build a simple, but surprisingly effective device called an ionization chamber or ion chamber , which is just a very sensitive current sensor, or resistance measuring device, the difference being only the point of view. A great source of information on ion chambers is: http://www.techlib.com/science/ion.html Ion chambers are not Geiger counters, however they work according to the same basic principles, as will later be explained. You will need to be able use soldering iron, and perform current and voltage measurement. If you don't know how to do these things, it's better to ask someone to show you. Please only perform the tasks written here if you know what you are doing. Soldering requires high temperature. We will work with high voltages at some

How does iptables hashlimit module work?

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*UPDATED* Hashlimit is an iptables module that allows one to define rules that in effect will limit traffic speed (bytes / time unit) or frequency (connections / time unit) per target or origin ports / IPs. The inner workings of this module and / or how to make it work correctly remains a mystery for many. Hashlimit is also close friends with the limit module, only much more powerful, capable of expressing rate limiting per source IP (for example) in a single rule.