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
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.