Eduroaming in Utrecht

eduroamEduroam is a great Wi-Fi login system for students and researches that works with certificates for secure access of on-campus Wi-Fi networks and has the added benefit that Eduroam users can attach to any other Eduroam network around the globe without changing their Wi-Fi configuration. That’s the theory and paper is patient. So when I recently was at the University of Utrecht in the Netherlands I tested if the theory holds up with an Eduroam setup of the University of Vienna.

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What Is My Theoretical Top Internet Speed?

Theoretical Internet speeds in fixed line and mobile networks keep rising, which is a nice thing. Unfortunately, round trip delay times are not decreasing at the same rate, mostly due to physical limits these days which at some point will limit the maximum throughput of a single TCP stream no matter how fat the pipe is and how fast a server can deliver data. So where is this limit?

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Good Advice To Block, Detect and Mitigate Ransomware Damage In Companies

Today I came across this great article by Robert Penz in which he describes measures how companies can reduce the risk of Ransomware encrypting their files on network shares and other devices in the local network. Also, he describes how a company can prepare itself in case it still happens to reduce their downtime as much as possible. I found one of his suggestions of particular interest: Snapshots of network shares.

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One German LTE Network Operator Now On-Air with 50 MHz

When it comes to investigative reporting in the telecommunication domain, German telecoms news website Teltarif certainly is at the forefront. Recently they noticed that the public network coverage maps of one of the network operators in Germany now show that in many cities, they have deployed LTE in three different frequency bands.

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LTE And The Number Of Simultaneously Connected Users

Recently I read this very interesting post that analyzed how many users can be connected to an LTE eNodeB simultaneously. As the author says in the article there is no single answer to this as many factors are playing into the game. From a pure uplink signaling point of view there can be well over 1000 users simultaneously in RRC-Connected state. In practice I wouldn’t be surprised if networks set that number way lower as that number is far too high to give anyone a halfway decent speed experience. So how many might there be connected simultaneously to a base station today? Let’s play with some numbers.

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So Glibc Is Not Statically Linked!?

When I first heard about the news of a serious security vulnerability in glibc I thought that I would soon see a lot of programs of my Linux distributions being updated. That’s because I faintly remember that I once read somewhere that in Linux, libraries are often compiled into the application instead of dynamically linked at runtime. But I guess that was not quite true, at least not for glibc anyway. So far I’ve only seen an update of the glibc library itself. Since then no other programs have been updated due to statically linking that library. So if that holds true we might have been luckier than I thought. Would be nice for a change!

Decoding An 802.11ac Beacon Frame

vht-beaconWifi 802.11ac with 80 MHz channels (Wave 1) have been on the market for some time now and high end notebooks and smartphones have started supporting the new standards. I’m still stuck with 802.11n on 5 GHz with 40 MHz channels but I do have an 802.11ac capable access point. So while I can’t use the functionality for the moment with my notebook I decided I could at least have a look at the Access Point’s 802.11ac capabilities by doing a Layer 2 Trace and capturing a Beacon Frame.

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