Access control and Basic authentication is performed before dispatching to a domain.
The following domains are standard with Tclhttpd:
Other domains can be created per-site, by including the domain handling code in the custom directory.
A new domain can be registered by means of the Url_PrefixInstall command, which maps a URL prefix to a tcl proc which handles all URLs with the given prefix.
Tclhttpd can roughly be functionally decomposed into