The Bristol Wireless LTSP suite

Bristol Wireless are a collective who run, among other things, a community-access wireless network in the Easton area of the city. Their LTSP suite is one of those other things.

I’ve been working with some of the Bristol Wireless crew at The St Werburghs Centre over the last few months, but it wasn’t until FAVE last Saturday that I got a chance to see the LTSP suite up and running, and I was so impressed I thought I’d write about it.

LTSP stands for the “Linux Terminal Server Project”. Simply put, a terminal server is a machine that runs applications on behalf of client machines – the terminals. This means you can use old or low-spec hardware to build clients and connect them to a more powerful machine which will actually do most of the work, enabling users to access applications on the clients that they’d be too slow or flakey to run without the server’s power.

[LTSP users at FAVE]

The Bristol Wireless LTSP suite is just such a patchwork of near-obsolete and flashy new hardware: a pile of ancient laptops donated by the local police force are connected to a powerful new Acer laptop boasting gigabytes of RAM using a bundle of Cat-5 and a gigabit ethernet switch. The Acer takes care of the bulk of the processing and the gigabit ethernet ensures that the connections are as fast as possible. Combine it with the satellite uplink from their collaborators Psand, and they’ve got a mobile IT facility that fits into the boot of a small car!

[The Terminal Server]

And it works like a charm. The clients are responsive and boast a wide range of applications and the whole system has proved a success with users: so far this summer it’s been taken to the Home Education Festival and the Big Green Gathering where it was a hit with the kids as well as the FAVE event where it proved popular among the geeks (like me, for example). As well as being a flexible community resource, the project is a great showcase for what can be achieved with some old hardware, Free software and a bit of ingenuity, and it provides a slick and impressive user experience for people coming to a Free software based system for the first time.

[More LTSP users at FAVE]

Given the fact that Bristol Wireless come across as a relaxed group who run their projects on an ad-hoc voluntary basis, this shows what they can put together when they get down to business. They are using LTSP to build IT suites elsewhere in the city and are expanding their operations to offer other services such as internet connectivity as well as access to the local wireless network (my employer, the St Werburghs Centre, is one of their new customers), so let’s hope their future projects continue to be as impressive.

(For more photos, see here.)

Brute force ssh password attacks

Since opening my SSH server at home to the internet yesterday – less than 24 hours ago – there have been 2883 failed attempts to log in from two ip addresses: and That makes me nervous, even though I’m reasonably confident that it’s secure due to password authentication being turned off and the following two handy iptables rules in force:

iptables -A INPUT -p tcp -m state --state NEW --dport 22 \ 
 -m recent --update --seconds 15 -j DROP 

iptables -A INPUT -p tcp -m state --state NEW --dport 22 \
 -m recent --set -j ACCEPT

I got this idea from a post to alt.os.linux.slackware. These rules use the recent extension to iptables to track attempted SSH connections and drop any that come from the same IP within 15 seconds. If you miss-type your passphrase, you just have to remember to hang back for a few seconds before retrying to avoid getting caught out. You could jump to a custom chain that logged such connections before dropping them if you felt the need to monitor the effectiveness of the rule – although the scripts usually just stop trying after a few connection attempts are dropped.

Worm related spamming

I got an email this morning from “Daphne Jacobsen”, a marketroid at a CD/DVD company that shall not be getting any plugs here. She claimed that someone from my company had mailed them requesting prices last week but that their servers had become infected with one of the many worms on the lose recently and that the message had been lost (but obviously not completely lost, otherwise where did she get the email address?) Her message ended:

In case you need more information, our company web site is [DELETED] where you can see we are a complete “one stop shop” for DVD, CDROM, printing, packaging, and fulfillment services.

If you need, please call me TOLL FREE at [DELETED].

Obviously spam. The mail was sent to an email address that I’ve never used at a domain I’ve only ever used for personal purposes. Interesting, though. The mail was obviously carefully written to sound genuine and unique. Hand-wringing over the problems caused by the “worm” ties it in nicely with current events on the internet and might make a receipient feel sympathetic to the sender. At first glance, not your usual spam – possibly different enough to not only escape spamtraps (it slipped past two to get to me) but to snare a few more unwary punters than usual. I’ve never received anything quite so carefully crafted before (if you exclude some of the better phishing emails).

Uma update (4)

Some more photos of Uma at last!

[Uma trying to crawl across the living room floor]


[Uma in her play ring covered in toys]

I’m thinking of putting new Uma photos into a private area of the website at some point in the fairly near future. If you’d like to have access to Uma piccies, drop me a line and let me know.

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FAVE 2005

The Free Audio and Video Event last Saturday at the Trinity Centre in Bristol was an intriguing day. There was a lot of stuff packed into the schedule and the subject matter varied quite considerably – not surprising given the scope of the event.

Frankly, some of the stuff went a bit over my head, but there was plenty there of interest and the day was a good opportunity to meet people and get ideas going. I was particularly interested by James Wallbank’s talk on the Access Space project in Sheffield, which is inspiring other people to start up similar projects across the UK. Access Space is a free media lab built using recycled hardware and Free software like Linux and run with a strong emphasis on collaboration: people can walk in and use the facilities for free but must be prepared to pitch in and help other users when they can. He talked of the success they’ve had getting young people interested and involved and it sounded like they have a lot to offer similar projects in terms of ideas and experience.

There was loads more. Tom Chance of Remix Reading gave an interesting talk which focused on the practical aspects of remixing creative commons licensed culture and pointed out the need for a large pool of material licensed under the same terms to avoid incompatibilities caused by license proliferation. A chap from Plugincinema gave a talk on open source film-making and it’s interfaces with open source software and internet culture. There was a presentation by Michael Sparks from the BBC on their open source Kamaelia project for large-scale media delivery – although I missed part of this talk and so should really go and read up on it some more.

Later the emphasis switched from theory to practice and there were performances and demonstrations of various kinds. One chap played long ambient techno tracks composed using free software while he surfed the web with his laptop display projected onto the screen behind him. We couldn’t quite work out whether this was some kind of postmodern performace or whether he was just randomly surfing around while he waited to introduce the next track. Quite a few people drifted over to the Bristol Wireless LTSP installation on one side of the hall, which really deserves a post all of its own, so watch this space.

All in all an interesting day, although I’d expected a few more people and it seemed that most attendees were already aware of Free/Open Source software and creative culture – “geeks talking to geeks” as someone put it to me at one point. In my limited experience this is a major sticking point when it comes to advocacy – it’s easy to reach people who’re already interested, but far more difficult to get beyond them and attract people who may not have thought about this way of doing things before.

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I ran across this meme the other day at Pete Ashton’s weblog, and as it’s been in the back of my head ever since, I thought that for once I’d take part (memes usually suffer the same fate as spam round these parts).

5ongs – five songs that I’m currently digging. OK. Here’s where I amuse everyone with my taste in music. None of these tracks are particularly new, fresh or cutting edge, but I like ’em all for various reasons. In no particular order:

  • P-Funk is playing at my house – LCD Soundsystem/DJ Riko feat. Gerald A and Katie Enlow (wicked remix!)
  • Women Lose Weight – Morcheeba featuring Slick Rick (“I heard he was displeased with her weight gain”)
  • Yeah (Crass Version) – LCD Soundsystem (rough!)
  • Lie to Me – Slam (melancholy)
  • Falling (Quantic Mix) – Nitin Sawhney (nice remix)

And just for fun, five nearly-made-it tracks:

  • Paper Underwear – David Holmes presents the Free Association
  • 70s 80s – Nightmares on Wax
  • Good Girl Gone Bad – Herbaliser featuring Wildflower
  • Lately (GES-E and Visionary Underground Mix) – Nitin Sawhney
  • Rikki – Mylo

If you feel like running with this one, please do – and link back here so I can pick up the reference. Ta.

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Enforced Downtime

In case any of my tiny number of visitors was wondering, this site was down yesterday between about 13:00 and 21:30 along with the entire webserver due to a “detected attempted compromise”. (I’m glad to say that everything seems to be as it was before the outage, as I’d neglected to take a backup for a week or two.)

If this site ever disappears and you’re wondering why, have a look at the status page at the website.

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Bristol Balloon Fiesta

There were strange beasts in the skies above our city tonight…

Balloons in silhouette

It’s the annual hot air balloon festival this weekend and tonight scores of them launched from Ashton Court and floated low over the city. We took Uma up to a nearby park to watch them rising into the sky against the setting sun.

Balloons in silhouette

It was pretty impressive, especially as the balloons were often low enough to carry on a conversation with their pilots!

Balloons in silhouette

The only problem was resisting the urge to spend the evening watching through the viewfinder on my camera rather than just sitting back and enjoying the spectacle. Last year we went up to Ashton Court to watch them all launch on the saturday (bloody crowded it was, too) and I ended up with a couple of hundred photos I’ve not looked at since.

Balloons in silhouette

Still, got some good shots this year. I might put a load more of them up on Flickr. If I get around to it. I have posted a load more on my Flickr account.

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Basic version control with wikieditish

At the St Werburghs Community Centre, we use Blosxom to power our website. As the other staff needed to be able to update and add content quickly and with the minimum of fuss, I combined the wikieditish plugin with TinyMCE and a couple of other scripts to create a simple rich-text web interface to the site.

During testing and the initial setup period, it became apparent that having the ability to roll an entry back to its original state after a dodgy edit would be a useful feature, so I added a few lines of code to wikieditish that supports a very simple kind of version control: every time a change is made, the plugin saves a copy of the current state of the post into a backup file. This file is over-written each time so you can only revert to the last saved version, but this allowed staff some scope for experimentation with the knowledge that they could undo any serious mistakes quickly.

I thought that I’d make this version of the plugin available here in case any other blosxom users might find it useful, so download, which contains the plugin and some basic flavour templates. I have not renamed the plugin itself, it is still simply named wikieditish, but I’ve added a bit of extra documentation and updated the version number to differentiate it. The version control behaviour is all optional and is off by default.

Atom 1.0 Support for Blosxom

Here is an updated atomfeed plugin that supports Atom 1.0: download atomfeed.

Changes since the last beta version:

  • Moved variable configuration to head sub
  • Added simple entity-unescaping in generation of the element
  • Adjusted the xml:base attribute to reflect $id_domain rather than $blosxom::url, and added the attribute at feed-level as well as for each entry

This plugin offers basic support for most of the specification, which should be enough for the vast majority of users. Not currently supported are the and elements. has been excluded as it seems an element more aimed at those publishing feeds aggregated from other feeds. probably could be supported, but would have been a bit of a kludge without the use of metadata – so anyone who needs this element could use the meta plugin and a custom template.

Of course, Atom is designed to be flexible and extensible and there are already people out there imagining losts of uses for the format – see this article at IBM Developer Works for some ideas (via Tim Bray). This plugin can never hope to cater for all possible uses, but it should be enough to provide the bare bones that others can build upon to meet their own needs.

The plugin comes with flavour templates and extensive documentation, including a list of all the variables it makes available for use in templates, notes on compatibility issues with other plugins and suchlike. I’ve extracted some of the major points below, but see the plugin itself for more complete notes.

  • The plugin has a large number of configurable variables and generates an even larger number of template variables. However, it is designed to be usable with only minimal configuration: set the variables $default_author and $feed_yr, drop the plugin into your $plugins_dir and off you go.
  • The plugin is intended to work with nothing but blosxom.cgi and a standard perl installation, but it will perform better if the XML::Parser and LWP modules are installed, and if you are using a plugin like entries_cache that stores the creation times of your posts.
  • If you are modifying the content of your entries using other plugins, particularly any that escape characters or add markup (like some of these), you should have them run before the atomfeed plugin. You want atomfeed to get each post in the state that it would be sent to a normal web browser.
  • Similarly, if you intend to use the config or prefs plugins to modify any of the variables generated by the plugin, they will need to run before it.
  • Podcasters: enclosures are supported. You need to link to your enclosure in the body of your weblog post, and provide the anchor tag with a rel attrubute of “enclosure”. For example: <a rel="enclosure" href="">Podcast for 5th August</a>. If you have the LWP module and you change the $use_full_enclosures configurable variable to “1”, the plugin will also include data on the length and content type of the enclosure (this is recommended as good practice).
  • You can include “related” and “via” links using a similar method – just ensure the anchor tags have an appropriate rel attribute for these links to be included in your feed as corresponding s.

Please post any feedback you have to the blosxom mailing list, maybe as a follow-up to this post.