Advanced Linux Networking

Chapter 11 discussed the use of pull mail servers, which allow users to read messages directed to them personally . This chapter covers a different type of messaging system: news servers. Where e-mail is a one-to-one correspondence, news (or Usenet news or Netnews, as it's often called) is a one-to-many transmission medium. A user may post a message to a news server, and any user of that news server may then read that message. What's more, news servers often communicate amongst themselves , resulting in propagation of messages across the world. Whether you run a news server that's only used locally or one that's connected to others, news servers can provide a useful group communication system for your users.

Traditional news servers talk to each other as equals, exchanging all messages in newsgroups. These servers support multiple clients on the same or other computers, which read a small subset of all messages. One variant on a regular news server is a program that connects to a conventional news server as a client in order to download only a subset of the messages that the local users want to read. Such miniature news servers are often run on personal computers to permit offline news reading ”rather than connect to the Internet and stay connected while reading news, the system can connect, download messages, and allow the user to read them while disconnected. This approach can minimize network connection times, which can be important if you're billed by the minute.

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