secret society of super sydney sysadmins

mibus.org

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A discussion came up during lunch at the IPv6 Roadshow… is NAT robust and well understood? Since this is kind-of an opinion piece, I’m not going to cite evidence; it’s just random experience and anecdote that (to me) makes a lot of sense. NAT is robust: NAT, for the sake of NAT – sure, maybe it’s robust (or “robust enough”). But even if you argue that NAT itself is robust, it in turn breaks a host of other things.

Moving!

I’ve been [comparatively] quiet for a while now, and I can finally announce the results of my endeavours: I’ve resigned from Internode (ie. iiNet) in order to accept a position at Google in Sydney. This means that Missy and I and our kids are all packing our bags and getting ready to head eastwards, looking forward to new and exciting adventures. FAQ: When? My last week in Adelaide is the week of the 22nd of April.

LCA2013

I presented “After Arduino” at LCA2013, explaining how to dig deeper into what “Arduino” really is, and how to get better control over your embedded devices. If you are just after the slides, PCB schematics, or example code, then you should grab them here: https://github.com/mibus/AfterArduino A video of the talk is available in MP4 and OGV formats (or if you’re with Internode, you can grab unmetered MP4 and unmetered OGV files).

I’m working on a GNOME-Shell plugin that can show alternate timezones. As part of the plugin, I want it to remember what the user’s selected timezone is. A good extension to pull apart seems to be the “System Monitor“. The “short version” of the minimum you need to do is as follows… Add a schema name to your metadata.json, eg: "settings-schema": "org.gnome.shell.extensions.system-monitor", (Replace “system-monitor” with a unique name for your own extension) Create a schemas directory inside your extension’s directory, and create a file inside that called YOURSCHEMANAME.gschema.xml, eg.

ping -f[aux flood]

I’m having trouble admitting this publicly, but I learnt something new recently about ping, of all things. To quote from the man page of ping: -f Flood ping. For every ECHO_REQUEST sent a period ``.'' is printed, while for ever ECHO_REPLY received a backspace is printed. This provides a rapid display of how many packets are being dropped. Seems reasonable enough. I mean, “flood” is pretty clear, right? Except, during troubleshooting this week I found that pinging a responding host and a non-responding host resulted in sending a different rate of packets.

Sometimes, you really need to get from point “A” to point “B”, but you can’t. Restrictive firewalls, poor change control, you don’t own the infrastructure, or maybe it’s just “temporary” and you don’t want to have to go to all that effort just for a few days. Struggle no more! SSH Port Forwarding Primer Let’s just say that you have an application on server “A”, and you want it to be able to reach a web service on your local desktop.

As many of you know, the company I work for (Internode) was recentlyish purchased by iiNet. iiNet’s headquarters is in Perth, which is 1.5 or 2.5 hours “behind” Adelaide time. There’s no longer a multi-timezone clock available for the panel, so… oh well I just wrote one myself. Right now, it only supports GMT+8 as the “remote” timezone, but it’s easy enough to change the code. The code is up on GitHub: https://github.com/mibus/MultiClock Thanks to Marco Dallagiacoma for writing the [“Fuzzy Clock” plugin][2], as I used it as a basis for my own code.

One of the things I’ve spent a lot of time with, has been EMC NetWorker (previously Legato NetWorker). A vaguely common issue is for a process of some kind – backups, staging to tape, restores, etc – for no reason just stop making any new progress. Once you’ve checked off the common reasons – like making sure you haven’t run out of disk space or usable tapes – it seems like the only option is to restart NetWorker as a whole, losing any in-progress actions (even ones that are to devices that haven’t stalled).

IPv6 for SysAdmins

IPv6 is a new and complicated piece of technology; like any new technology it takes a while to get used to and discover what does and doesn’t really work. Who am I? I’m Robert Mibus, and I helped roll out many of the IPv6-enabled services at Internode (now part of iiNet). I’m writing this based on my personal experience and opinion, so even though I reference Internode frequently, please don’t consider any of the below official communication from them, OK?

Just to illustrate the insanity of ABC’s position in the takedown of Python-iView – here is how to “download” the latest Doctor Who episode from iView, without using an application that infringes the takedown notice as I understand it. Update: To be clear, this may well still violate the iView Terms of Service… that I’ve never read, and that you don’t get prompted to if you follow the below; the below I pieced together without use of the site.