Dynamic Subdomain Configuration

[justin]

How do I handle the fallback, i.e. somebody types:

    foobar.mydomain.com

Which does not exists, right now I am getting: no input file. Instead,
would love to simply return a 404 error, or even better serve a custom
static 404 error page.

Maxim:

Bummer that error_log does not support variables, anyway to do this
dynamically?

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,222733,222746#msg-222746