Книга: Linux Network Administrator Guide, Second Edition

C News in an NFS Environment

C News in an NFS Environment

A simple way to distribute news within a local network is to keep all news on a central host and export the relevant directories via NFS so that newsreaders may scan the articles directly. The overhead involved in retrieving and threading articles is significantly lower than NNTP. NNTP, on the other hand, wins in a heterogeneous network where equipment varies widely among hosts, or where users don't have equivalent accounts on the server machine.

When you use NFS, articles posted on a local host have to be forwarded to the central machine because accessing adminstrative files might otherwise expose the system to race conditions that leave the files inconsistent. Also, you might want to protect your news spool area by exporting it read-only, which also requires forwarding to the central machine.

C News handles this central machine configuration transparently to the user. When you post an article, your newsreader usually invokes inews to inject the article into the news system. This command runs a number of checks on the article, completes the header, and checks the file server in /etc/news. If this file exists and contains a hostname different from the local host's name, inews is invoked on that server host via rsh. Since the inews script uses a number of binary commands and support files from C News, you have to either have C News installed locally or mount the news software from the server.

For the rsh invocation to work properly, each user who posts news must have an equivalent account on the server system, i.e., one to which she can log in without being asked for a password.

Make sure that the hostname given in server literally matches the output of the hostname command on the server machine, or else C News will loop forever in an attempt to deliver the article. We discuss NFS is detail in Chapter 14, The Network File System.

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