httpd is the hyper text transfer protocol daemon

it runs on the server, and it can run on any unix system

the daemon runs continually, listening (port 80) for requests

requests come from browsers, primarily, for documents of particular types

the mime.types configuration file tells the daemon how to interpret the data in the files it gets

in most cases, the daemon relies on the file name sufix (eg .gif) to tell it what the file type is

files are sent in parts, and connections with remote clients are verified until the whole file arrives (and is reassembled)

the httpd.conf file holds variables pertinent to the running of the daemon

there's lots more info about apache (the sub-species of httpd we're using) on their web site

there are several logs that you can "cat" to see what is going on here, such as /etc/httpd/logs/access_log and /etc/httpd/logs/error_log