If you are secondary for a lot of zones, you may find it convenient to split your named.boot file into a static portion which hardly ever changes (directives such as directory, sortlist, xfrnets and cache could go here), and dynamic portions that change frequently (all of your primary directives might go in one file, and all of your secondary directives might go in another file -- and either or both of these might be fetched automatically from some neighbor so that they can change your list of secondary zones without requiring your active intervention). You can accomplish this via the include directive, which takes just a single file name as its argument. No quotes are needed around the file name. The file name will be evaluated after the name server has changed its working directory to that specified in the directory directive, so you can use relative pathnames if your system supports them.