networking config is distribution dependent, check the distro's docs on those.
But in general you have to consult the program in question to find out what config files it uses. Debian follows a nice scheme of putting most config files in a subdirectory of /etc named after the program, like /etc/apache holds the config files for Apache, but some config files must go directly in /etc and creating a dir for 1 config file seems like overkill for smaller apps. As for RedHat, I'm not sure how they do things.
'man -k something' will search the man page descriptions for something and tell you which pages mention it.