802.1x Authentication on Debian

I recently had to setup some Linux workstations with 802.1x authentication (described as “Ethernet authentication”) to connect to a smart switch. The most useful web site I found was the Ubuntu help site about 802.1x Authentication [1]. But it didn’t describe exactly what I needed so I’m writing a more concise explanation. The first thing […]


Nexus 6P and Galaxy S5 Mini

Just over a month ago I ordered a new Nexus 6P [1]. I’ve had it for over a month now and it’s time to review it and the Samsung Galaxy S5 Mini I also bought. Security The first noteworthy thing about this phone is the fingerprint scanner on the back. The recommended configuration is to […]

Mobile Phones Review


In Australia we are about to have a federal election, so we inevitably have a lot of stupid commentary and propaganda about politics. One thing that always annoys me is the claim that we shouldn’t have small parties. We have two large parties, Liberal (right-wing, somewhat between the Democrats and Republicans in the US) and […]


Sysadmin Skills and University Degrees

I think that a major deficiency in Computer Science degrees is the lack of sysadmin training. Version Control The first thing that needs to be added is the basics of version control. CVS (which is now regarded as obsolete) was initially released when I was in the first year of university. But SCCS and RCS […]


I Just Ordered a Nexus 6P

Last year I wrote a long-term review of Android phones [1]. I noted that my Galaxy Note 3 only needed to last another 4 months to be the longest I’ve been happily using a phone. Last month (just over 7 months after writing that) I fell on my Note 3 and cracked the screen. The […]

Mobile Phones

Xen CPU Use per Domain again

8 years ago I wrote a script to summarise Xen CPU use per domain [1]. Since then changes to Xen required changes to the script. I have new versions for Debian/Wheezy (Xen 4.1) and Debian/Jessie (Xen 4.4). Here’s a new script for Debian/Wheezy: #!/usr/bin/perl use strict; open(LIST, "xm list --long|") or die "Can't get list"; […]


BIND Configuration Files

I’ve recently been setting up more monitoring etc to increase the reliability of servers I run. One ongoing issue with computer reliability is any case where a person enters the same data in multiple locations, often people make mistakes and enter slightly different data which can give bad results. For DNS you need to have […]


Ethernet Interface Naming With Systemd

Systemd has a new way of specifying names for Ethernet interfaces as documented in systemd.link(5). The Debian package should keep working with the old 70-persistent-net.rules file, but I had a problem with this that forced me to learn about systemd.link(5). Below is a little shell script I wrote to convert a basic 70-persistent-net.rules (that only […]



At LCA I attended a talk about Unikernels. Here are the reasons why I think that they are a bad idea: Single Address Space According to the Unikernel Wikipedia page [1] a significant criteria for a Unikernel system is that it has a single address space. This gives performance benefits as there is no need […]


Compatibility and a Linux Community Server

Compatibility/interoperability is a good thing. It’s generally good for systems on the Internet to be capable of communicating with as many systems as possible. Unfortunately it’s not always possible as new features sometimes break compatibility with older systems. Sometimes you have systems that are simply broken, for example all the systems with firewalls that block […]