News servers tend to be used in three ways:
Both full Usenet news and internal news use the same software. The main theoretical difference between the connected and isolated systems is one of the external connection or lack thereof. In practice, there's another major difference: A full Usenet news server (one that hosts more than a trivial fraction of the thousands of available newsgroups) consumes a great deal of disk space and network bandwidth in exchanging the news messages. A system that hosts a full Usenet news server is likely to require so much disk space and bandwidth that it won't be useful for much of anything else. Such a system will need a hard disk that's tens or even hundreds of gigabytes in size just for the news articles. Of course, a system with much more limited newsgroup availability, such as a personal system intended for offline news reading, won't have such huge resource requirements.
Because of the need for dedicating an entire computer and bandwidth that's measured in megabits per second to a full Usenet news server, it's unlikely that a small office or home will need such a server. Instead, such users are better served by using their ISPs' news server or a third-party news server. (Some popular commercial news providers include Giganews, http://www.giganews.com; Supernews, http://www.supernews.com; and NewsGuy, http://www.newsguy.com. You can find a list of free third-party news servers at http://www.newsservers.net. The http://groups.google.com archive site holds archives of many popular newsgroups, accessible through a Web-based interface.) The discussion of regular news servers in this chapter (in the section "Running INN") focuses on the internal communications use of a news server, although it doesn't completely ignore the data transfer configuration required of a regular Usenet news server.
Offline news reading is often done through a feature of news readers (news client programs), but it can be done through a special limited-function news server, such as the Leafnode program described in the "Using Leafnode" section of this chapter. Such programs have different configuration requirements than do conventional news servers, but they work much the same from the client's point of view. If you have a full-time connection to the Internet (via a corporate LAN or home broadband account), chances are you'll find it easier to use your ISP's news server directly rather than use an intermediate news server. You might use such an option when your Internet connection is limited or costly, or if your ISP's news server is overloaded when you want to use it ”you can configure Leafnode to transfer messages during off hours, thus making your news reading quicker. You might also want to use Leafnode if your system serves one or two dozen people who read largely the same newsgroups, because in such a scenario, running your own server can reduce your external news- related data traffic.