[Sussex] web security glitch!!

[Geoffrey Teale]

On Jul 9, 2008, at 5:49 PM, Steve Redshaw wrote:

> It is fascinating being part of the SLUG discussions (just to remind  
> folk that I am a very green Linux user, trying to wrench myself away  
> from Windows) and I am slowly learning more, but there are  
> constantly obstacles which I find frustrating and off-putting,  
> mostly in the form of Linux jargon and assumed knowledge of computer  
> technology.
>
I appologise for that, it is sometimes hard to judge what level the  
people in a discussion are at.

> The advantage of Windows, as mentioned in another recent posting, is  
> its adaptability to many different computers and hardware  
> attachments, you just install it and it works with just about  
> everything. I am not trying to demean Linux, but in my limited  
> experience, it is a lot harder creating a computer system with Linux  
> than it is with Windows.
>

Well the it just works thing really isn't true, and the comments made  
by the Tescos chap were naive at best.  The spirit of what you say is  
correct though, hardware manufacturers bend over backwards to make  
their hardware work on Windows and often don't provide any support for  
Linux.   This has almost nothing to do with the technical merits or  
design of either system and everything to do with market economics and  
the Fear, Uncertainty and Doubt (FUD) and other bully boy tactics  
Microsoft uses to control the hardware market.

All of that is a distraction from the point however.

> An example of something I don't understand at all!!
>
> "Surely any distribution with network based package management and a  
> cron daemon running?
>
> Though whether that is a sensible strategy or not I will leave as an  
> exercise for the reader..."
> Geoffrey could you elaborate please?


Surely.  So there are two parts to this.  Firstly there is package  
management.   I'll take a Debian derived distro (Such as Debian,  
Ubuntu or Mint) as an example, but there are parrallels these days in  
most distribution (including those based on the RPM package system or  
my favourite, Arch linux's pacman system).   These distribution use  
the .deb package format in conjunction with the apt suite of  
management tools.   In particular these tools allow for:

    * Continuos updates of available packages across the internet
    * Automatic installation of packages and dependencies.
    * Multi package repositories

These features allow Debian, Ubunutu, etc to define a repository for  
security updates to a particular release.   If you run Ubuntu on your  
desktop then you'll see a nice GUI tool that routinely checks for  
updates and asks you if you want to apply them.   Behind this tool  
however is a lower level library that provides this functionality and  
it also available through command line tools.    Because you can  
perform an upgrade on the command line you can also schedule this task  
to happen at regular intervals.   The UNIX way of scheduling tasks to  
run is a daemon (on Windows you'd call this a service, on UNIX you all  
it a daemon)  called cron.

I'd suggest at this point going away and looking up:

    * cron
    * crontab -e

.. if you're interested in this sort of thing, and then coming back  
with questions.   Be warned, cron can seem a little arcane at first,  
but there is a wealth of knowledge here to help if you have problems.

-- 
Geoffrey Teale
Software and Technology Consultant, München
tealeg at member.fsf.org