whereami - Network Autoconfiguration Utility

WARNING! This documentation is seriously out of date. The most up-to-date documentation for this is all in the man pages included in the Debian package for whereami. The most up-to-date version of whereami is, in fact, the one that is in the Debian unstable release.

In May 2005 I have now added these mailing lists, which should be able to provide more up-to-date information...

• A Whereami Announce mailing list, which should be very low volume (release announcements really).
• A Whereami Discuss mailing list, which is likely to also be very low volume, for discussion of proposals for enhancements, questions about operation, publishing your tricks, assisting newbies, and so on.

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What?

whereami automatically configures your system during boot and whenever a PCMCIA network card is inserted or removed:

• Testing available networks
• Testing available hardware
• Building an appropriate configuration script
• Executing the configured script

Since this all happens on PCMCIA card removal or insertion (or whenever else you set it to happen), it should be easy to automate all the actions you would normally take manually when you arrive at a new location.

Why?

I sit down to work at quite a variety of places. When I am there I'm generally there for a whole week and its a pain if it takes me half a morning to get the network set up and so on. Well, I could write scripts to tell my computer where I am, but that's no challenge!

So I like to have my computer automatically know where it is, set the mail, web and so forth automatically without me having to worry about it and I can concentrate on getting my job done :-)

Other considerations which have made me design this framework in this way include:

• Easy extension to new situations
• Easy to enhance functionality through new helper scripts
• A component-based framework which I (and others) can enhance piecemeal

How?

whereami splits the problem of re-configuration into several parts:

• When can we legitimately arrive or leave a location
• Detection of where you are
• Configuration to suit the environment

Moving from Location to Location

My feeling is that there are only a few actual times when a laptop might find itself in a new 'location': during the boot process, and when a PCMCIA (network) card is inserted or removed.

whereami runs at each of these times, after basic hardware initialisation, to detect and configure the more high-level components of the system such as bind and sendmail.

Detection of the Current Location

All tests are separate small scripts, which are executed by whereami in order until one indicates that it has been successful.

The use of scripts gives the flexibility to detect locations other than simply through identification of details of the network topography, for example the ability to detect special hardware such as a docking station or an extra hard drive. It also makes it easier for the user to allow changes to the behaviour for fall-through specifications.

Since these scripts are each generally no more than a few lines, they should be easily understood by a novice, even where a single script to do the whole job might be confusing.

For full details of setting up location 'test' scripts, look here

Configuring for the Location

Once the location has been identified whereami builds a location script comprised of actions to execute:

• When you 'leave' a location
• When you 'arrive' at a location
• When you are at a location

For full details of configuring actions, look here

Where?

All versions are here, in case there is an issue with one and you need to revert.

• Debian Packages
• Generic Packages

Who?

Written by Andrew McMillan