Книга: Linux Network Administrator Guide, Second Edition

The active and newsgroups files

The active and newsgroups files

The active and newsgroups files are used to store and describe the newsgroups hosted by this news server. They list which newsgroups we are interested in receiving and serving articles for, and administrative information about them. These files are found in the /var/lib/news/ directory.

The active file determines which newsgroups this server supports. Its syntax is straightforward. Each line in the active file has four fields delimited by whitespace:

name himark lomark flags

The name field is the name of the newsgroup. The himark field is the highest number that has been used for an article in that newsgroup. The lomark field is the lowest active number in use in the newsgroup. To illustrate how this works, consider the follow scenario. Imagine that we have a newly created newsgroup: himark and lowmark are both 0 because there are no articles. If we post 5 articles, they will be numbered 1 through 5. himark will now equal 5, the highest numbered article, and lowmark will equal 1, the lowest active article. If article 5 is cancelled there will be no change; himark will remain at 5 to ensure that that article number is not reallocated and lowmark will remain at 1, the lowest active article. If we now cancel article 1, himark will remain unchanged, but lowmark will now equal 2, because 1 is no longer active. If we now post a new article, it will be assigned article number 6, so himark will now equal 6. Article 5 has been in use, so we won't reassign it. lowmark remains at 2. This mechanism allows us to easily allocate unique article numbers for new articles and to calculate approximately how many active articles there are in the group: himark-lowmark.

The field may contain one of the following:

y

Posting directly to this news server is allowed.

Posting directly to this news server is not allowed. This prevents newsreaders from posting directly to this news server. New articles may only be received from other news servers.

m

The group is moderated. Any articles posted to this newsgroup are forwarded to the newsgroup moderator for approval before they enter the newsgroup. Most newsgroups are unmoderated.

j

Articles in this group are not kept, but only passed on. This causes the news server to accept the article, but all it will do with it is pass it to the "up-stream" news servers. It will not make the articles available to newsreaders reading from this server.

x

Articles cannot be posted to this newsgroup. The only way that news articles are delivered to this server is by feeding them from another news server. Newsreaders may not directly write articles to this server.

=foo.bar

Articles are locally filed into the ``foo.bar'' group.

In our simple server configuration we'll carry a small number of newsgroups, so our /var/lib/news/active file will look like:

control 0000000000 0000000001 y
junk 0000000000 0000000001 y
rec.crafts.brewing 0000000000 0000000001 y
rec.crafts.brewing.ales 0000000000 0000000001 y
rec.crafts.brewing.badtaste 0000000000 0000000001 y
rec.crafts.brewing.brandy 0000000000 0000000001 y
rec.crafts.brewing.champagne 0000000000 0000000001 y
rec.crafts.brewing.private 0000000000 0000000001 y

The himark and lomark numbers in this example are those you would use when creating new newsgroups. The himark and lomark numbers will look quite different for a newsgroup that has been active for some time.

The newsgroups file is even simpler. It provides one-line descriptions of newsgroups. Some newsreaders are able to read and present this information to a user to help them decide whether they want to subscribe.

The format of the newsgroups file is simply:

name description

The name field is the name of a newsgroup, and the ‹description is a single line description of that newsgroup.

We want to describe the newsgroups that our server supports, so we'll build our newsgroups file as follows:

rec.crafts.brewing.ales         Home brewing Ales and Lagers
rec.crafts.brewing.badtaste     Home brewing foul tasting brews
rec.crafts.brewing.brandy       Home brewing your own Brandy
rec.crafts.brewing.champagne    Home brew your own Champagne
rec.crafts.brewing.private      The Virtual Brewery home brewers group

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