Supporting Messaging Clients

Understanding How Articles Are Viewed

This section provides an overview of how users view articles. Users can view newsgroup articles using a news client such as Outlook Express.

The first step in viewing newsgroup articles is getting a list of available newsgroups. The client connects to an NNTP virtual server and requests the list of available newsgroups. NNTP Service receives the connection request, and through a process called authentication, verifies that the user is authorized to access newsgroups. If the user is authenticated, NNTP Service sends the client a list of all available newsgroups. By default, this communication takes place over TCP port 119, and an SSL port of 563.

The second step is selecting a newsgroup to view. The user can select a newsgroup from the list he or she receives. When the user selects an article, a request for that article is sent to NNTP Service, which returns the contents of the article. The following diagram illustrates the steps in this process.

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