There are very good online sources of information, most of which are collected at The Linux Documentation Project (http://www.tldp.org
). Check out the Guide named "The Linux Network Administrator's Guide, Second Edition" (http://www.tldp.org/LDP/nag2/index.html
) for details on network setups. What might be more helpful are the "How-To" documents, which describe step-by-step how people have set up their systems. See http://www.tldp.org/HOWTO/HOWTO-INDEX/categories.html
for a list of categories, and go to the Networking section.
For Apache, there's not only a number of good How-To docs at
but the Apache project also has produced a wealth of documentation at http://httpd.apache.org/docs-2.0/.
Of course, there's way more information than you really need in all of the above, but after reading enough to find what you need, you'll really know your stuff!
I can't help you with your DSL setup because I haven't used those tools, but there's lots of people on here who can. Search this forum (and the Linux Software forum) for "DSL RedHat" and I'll bet you find some helpful info.
As for turning your web server on and off once you've got it all working, this is easy: from the cute red hat icon in your desktop's tool panel, go to System Settings->Server Settings->Services, and up comes a window listing all your services. Select the "httpd" service from the list, and start or stop it using the toolbar buttons.
Hey! There's also a "HTTP Server" item on that Server Settings menu, which lets you do some of the basic Apache setup you need. Try that first to see if it will do the configuration work you need.
BTW: you can have programs turn Apache on and off using the "service" command, such as:
service httpd stop
to stop it. The program must be running as the superuser.