Usenet News

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Usenet is an open mail system on which users post messages that include news, discussions, and opinions. It operates like a mailbox that any user on your Linux system can read or send messages to. Users' messages are incorporated into Usenet files, which are distributed to any system signed up to receive them. Each system that receives Usenet files is referred to as a site. Certain sites perform organizational and distribution operations for Usenet, receiving messages from other sites and organizing them into Usenet files, which are then broadcast to many other sites. Such sites are called backbone sites, and they operate like publishers, receiving articles and organizing them into different groups.

To access Usenet news, you need access to a news server. A news server receives the daily Usenet newsfeeds and makes them accessible to other systems. Your network may have a system that operates as a news server. If you are using an Internet service provider (ISP), a news server is probably maintained by your ISP for your use. To read Usenet articles, you use a newsreader—a client program that connects to a news server and accesses the articles. On the Internet and in TCP/IP networks, news servers communicate with newsreaders using the Network News Transfer Protocol (NNTP) and are often referred to as NNTP news servers. Or you could also create your own news server on your Linux system to run a local Usenet news service or to download and maintain the full set of Usenet articles. Several Linux programs, called news transport agents, can be used to create such a server. This chapter focuses on the variety of news readers available for the Linux platform. The configuration administration and architecture of the NNTP server are covered in Chapter 26.

Usenet files were originally designed to function like journals. Messages contained in the files are referred to as articles. A user could write an article, post it in Usenet, and have it immediately distributed to other systems around the world. Someone could then read the article on Usenet, instead of waiting for a journal publication. Usenet files themselves were organized as journal publications. Because journals are designed to address specific groups, Usenet files were organized according to groups called newsgroups. When a user posts an article, it is assigned to a specific newsgroup. If another user wants to read that article, he or she looks at the articles in that newsgroup. You can think of each newsgroup as a constantly updated magazine. For example, to read articles on the Linux operating system, you would access the Usenet newsgroup on Linux. Usenet files are also used as bulletin boards on which people carry on debates. Again, such files are classified into newsgroups, though their articles read more like conversations than journal articles. You can also create articles of your own, which you can then add to a newsgroup for others to read. Adding an article to a newsgroup is called posting the article.

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The Google Web site maintains online access to Usenet newsgroups. It has the added capability of letting you search extensive newsgroup archives. You can easily locate articles on similar topics that may reside in different newsgroups. Other sites such as Yahoo maintain their own groups that operate much like Usenet newsgroups, but with more supervision.

Linux has newsgroups on various topics. Some are for discussion, and others are sources of information about recent developments. On some, you can ask for help for specific problems. A selection of some of the popular Linux newsgroups is provided here:

Newsgroup	Topic
comp.os.linux.announce	Announcements of Linux developments
comp.os.linux.admin	System administration questions
comp.os.linux.misc	Special questions and issues
comp.os.linux.setup	Installation problems
comp.os.linux.help	Questions and answers for particular problems
linux.help	Obtain help for Linux problems

You read Usenet articles with a newsreader, such as KNode, Pan, Mozilla, trn, or tin, which enables you to first select a specific newsgroup and then read the articles in it. A newsreader operates like a user interface, enabling you to browse through and select available articles for reading, saving, or printing. Most newsreaders employ a sophisticated retrieval feature called threads that pulls together articles on the same discussion or topic. Newsreaders are designed to operate using certain kinds of interfaces. For example, KNode is a KDE newsreader that has a KDE interface and is designed for the KDE desktop. Pan has a GNOME interface and is designed to operate on the GNOME desktop. Pine is a cursor-based newsreader, meaning that it provides a full-screen interface that you can work with using a simple screen-based cursor that you can move with arrow keys. It does not support a mouse or any other GUI feature. trn uses a simple command line interface with limited cursor support. Most commands you type in and press ENTER to execute. Several popular newsreaders are listed in Table 13-3.

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Numerous newsreaders currently are under development for both GNOME and KDE. You can check for KDE newsreaders on the software list on the K Desktop Web site at apps.kde.com. For GNOME newsreaders, check Internet tools on the software map on the GNOME Web site at www.gnome.org. The Mozilla newsreader is integrated into the Mozilla Web browser and is available from www.mozilla.org.

Most newsreaders can read Usenet news provided on remote news servers that use the NNTP. Many such remote news servers are available through the Internet. Desktop newsreaders, such as KNode and Pan, have you specify the Internet address for the remote news server in their own configuration settings. Several shell-based newsreaders, however, such as trn and tin, obtain the news server's Internet address from the NNTPSERVER shell variable. Before you can connect to a remote news server with such newsreaders, you first have to assign the Internet address of the news server to the NNTPSERVER shell variable, and then export that variable. You can place the assignment and export of NNTPSERVER in a login initialization file, such as .bash_profile, so that it is performed automatically whenever you log in. Administrators could place this entry in the /etc/profile file for a news server available to all users on the system.

Table 13-3: Linux Newsreaders

Newsreader	Description
Pan	GNOME Desktop newsreader
KNode	KDE Desktop newsreader
Mozilla	Web utility with newsreader capabilities (X-based)
Sylpheed	GNOME Windows-like Newsreader
Slrn	Newsreader (cursor-based)
Emacs	Emacs editor, mail client, and newsreader (cursor-based)
trn	Newsreader (command line interface)
tin	Newsreader (command line interface)

$ NNTPSERVER=news.domain.com $ export NNTPSERVER 

News Transport Agents

Usenet news is provided over the Internet as a daily newsfeed of articles and postings for thousands of newsgroups. This newsfeed is sent to sites that can then provide access to the news for other systems through newsreaders. These sites operate as news servers; the newsreaders used to access them are their clients. The news server software, called news transport agents, is what provides newsreaders with news, enabling you to read newsgroups and post articles. For Linux, three of the popular news transport agents are INN, Leafnode, and Cnews. Both Cnews and Leafnode are small and simple, and useful for small networks. INN is more powerful and complex, designed with large systems in mind (see www.isc.org for more details).

Daily newsfeeds on Usenet are often large and consume much of a news server's resources in both time and memory. For this reason, you may not want to set up your own Linux system to receive such newsfeeds. If you are operating in a network of Linux systems, you can designate one of them as the news server and install the news transport agent on it to receive and manage the Usenet newsfeeds. Users on other systems on your network can then access that news server with their own newsreaders.

If your network already has a news server, you needn't install a news transport agent at all. You only have to use your newsreaders to remotely access that server (see NNTPSERVER in the preceding section). In the case of an ISP, such providers often operate their own news servers, which you can also remotely access using your own newsreaders, such as KNode and Pan. Remember, though, that newsreaders must take the time to download the articles for selected newsgroups, as well as updated information on all the newsgroups.

You can also use news transport agents to run local versions of news for only the users on your system or your local network. To do this, install INN, Leafnode, slrnpull, or Cnews and configure them just to manage local newsgroups. Users on your system could then post articles and read local news.

Mailing Lists

As an alternative to newsgroups, you can subscribe to mailing lists. Users on mailing lists automatically receive messages and articles sent to the lists. Mailing lists work much like a mail alias, broadcasting messages to all users on the list. Mailing lists were designed to serve small, specialized groups of people. Instead of posting articles for anyone to see, only those who subscribe receive them. Numerous mailing lists, as well as other subjects, are available for Linux. For example, at the www.gnome.org site, you can subscribe to any of several mailing lists on GNOME topics, such as [e-mail], which deals with GNOME desktop themes. You can do the same at lists.kde.org for KDE topics. At www.liszt.com, you can search for mailing lists on various topics. By convention, to subscribe to a list, you send a request to the mailing list address with a –request term added to its username. For example, to subscribe to [e-mail], you send a request to [e-mail]. At www.linux.org, you can link to sites that support Linux-oriented mailing lists, such as the Red Hat mailing lists page and the Linux Mailing Lists Web site. Lists exist for such topics as the Linux kernel, administration, security, and different distributions. For example, linux-admin covers administration topics, and linux-apps discusses software applications. vger.kernel.org provides mailing list services for Linux kernel developers.

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You can use the Mailman and Majordomo programs to automatically manage your mailing lists. Mailman is the GNU mailing list manager, included with Red Hat. You can find out more about Majordomo at www.greatcircle.com/majordomo, and about Mailman at sourceforge.net.

Newsreaders

A variety of newsreaders are available for use on Red Hat Linux, including several specialized tools. Like the mail clients, there are newsreaders based on GNOME, KDE, Web interfaces, and the command line interface. All will work on any desktop, though those for the command line will use a terminal window to operate. GNOME newsreaders include Pan and Sylpheed, KDE provides KNode, Mozilla supports newsreader capabilities, and Pine and slrn use a command line interface. In addition, specialized tools like inews are available to post news articles. If you just want to download and decode binaries attached to articles, you can use Glitter to detect, download, combine, and decode binary applications posted as several encoded news articles. Check the GNOME and KDE software sites for the latest GNOME and KDE newsreader applications, www.gnome.org and apps.kde.org.

Pan is a powerful newsreader that lets you sort articles, decode binaries, and set up rules for selecting articles. Pan features both pane and notebook displays. Initially, newsgroups, article headers, and article contents are displayed in three panes. You can switch to a notebook display that will show each pane as a tabbed panel covering the entire window. In the newsgroup pane, a drop-down menu lets you choose whether to display all newsgroups or only subscribed ones. You can also search for particular newsgroups. For the article headers, an icon bar lets you display read or unread articles, as well as save and search articles. A selected article is displayed in the pane below the headers.

KNode is currently the standard newsreader distributed with KDE 2.0 with Red Hat 7.2. The KNode newsreader includes standard features such as follow-ups, saving and printing articles, article and newsgroup searches, and thread displays. It also supports more powerful features such as binary encoding and decoding, displaying attached image files, and separate window displays for articles. In addition, it supports multiple accounts, and customized configuration for features such as colors, fonts, window displays, and article search filters. You can find out more about KNode at knode.sourceforge.net. Other KDE newsreaders such as krn and kng are also available. You can download them from apps.kde.com.

The Mozilla newsreader is part of the Mozilla Web browser. You can set up and configure news accounts by selecting the Mail/News Account Settings from the Edit menu. This displays a sidebar that will include any news server you have already set up. To create a new news account, click the New Account button. This opens a series of dialog boxes where you enter in information such as your news server address and e-mail address. An initial screen asks you to choose whether you are setting up a newsgroup or a mail account. Once you have created your news account, you can then click it to display panes where you can set other options, such as the number of articles to display at a time.

The slrn newsreader is screen-based, with an interface similar to Pine's. Commands are displayed across the top of the screen and can be executed using the listed keys. Different types of screens exist for the newsgroup list, article list, and article content, each with its own set of commands. An initial screen lists your subscribed newsgroups with commands for posting, listing, and subscribing to your newsgroups.

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When you start slrn for the first time, you will have to create a .jnewsrc file in your home directory. Use the following command: slrn -f .jnewsrc -create. Also, you will have to set the NNTPSERVER variable and make sure it is exported (see Chapter 8).

The slrn newsreader features a new utility called slrnpull that you can use to automatically download articles in specified newsgroups. This allows you to view your selected newsgroups offline. slrnpull was designed as a simple single-user version of Leafnode. slrnpull will access a news server and download its designated newsgroups, making them available through slrn whenever the user chooses to examine them. Newsgroup articles are downloaded to the SLRNPULL_ROOT directory. On Red Hat, this is /var/spool/srlnpull. The selected newsgroups to be downloaded are entered in the slrnpull.conf configuration file placed in the SLRNPULL_ROOT directory. In this file, you can specify how many articles to download for each group and when they should expire. To use slrn with slrnpull, you will have to further configure the .slrnrc file to reference the slrnpull directories where newsgroup files are kept.

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Two other popular command line–based newsreaders are trn and tin. Though not distributed with all distributions, you can download versions from www.gnu.org.

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The GNU version of Emacs also includes a newsreader along with other components, such as a mailer and an editor. Check the Emacs Web site at www.emacs.org for more information. When you start up GNU Emacs, menu buttons are displayed across the top of the screen. If you are running Emacs in an X Window System environment, you have full GUI capabilities and can select menus using your mouse. Be sure the NNTPSERVER variable is set to your news server address in your .bash_profile file and it is exported.

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