Automatic subdomain configuration

Does anyone know how some servers programtically set up subdomains?

Like

john.blogspot.com
jeff.blogspot.com
more.blogspot.com

Is there a configuration file that contains this information? Are there settings in the htaccess file that can do this?

At the moment, I need to create subdomains manually, but I want to automate it.

JM

You should check to see if your server comes with Plesk, Ensim, cPanel, etc ... which automates the management of these tasks. If nothing is available you might look into Webmin at http://www.webmin.com or maybe grab a book on Linux server mgmt.

Otherwise you need to investigate DNS and Bind as well as Apache and virtual hosts (hint: check the bottom of the /etc/httpd.conf file for the virtual hosts section).