Rubber duck debugging is the process of explaining your problem out loud to a suitableobject (a rubber ducky or another person, take your pick); thealternate version is to write down your problem, for example in agrumbling blog entry or an email. This may sound very peculiar ifyou've never done it, but it works surprisingly well.

(Obligatory attribution dammit to the Centresource.com blog entry on it.)

As it happens, my leading explanation for why this works so well hasalready been

As part of automatic installs of Fedora Core, our customization stepinstalls of the current Red Hat updates from a local mirror. We use yum for this, because it both handles dependencies and uses compactmetadata files instead of having to read all of the update and base OSRPMs themselves. (We have 100 megabit networks, but it still adds upand slows down installs.)

We do this by feeding yum a custom configuration file; basically wetake the standard /etc/yum.conf file and add

If a piece of information doesn't have to be correct for the systemto work, sooner or later it won't be.

(Yanked out of my spam by ASN summary , where aversion of it got a mention in passing.)

It's easy to see this aphorism in action. For example, if yourhost/domain name to IP address mapping information is wrong you noticeright away. But nothing common breaks if the information to map froman IP address to a hostname is missing,