[ Pobierz całość w formacie PDF ]
.You should make surethat virtually all files in these directories are owned by user news or group news.Most problems arisefrom files being inaccessible to C News.Use su to become the user news before you touch anything inthe directory.The only exception is the setnewsids command, which is used to set the real user ID ofsome news programs.It must be owned by root and have the setuid bit set.In this chapter, we describe all C News configuration files in detail and show you what you have to do tokeep your site running.Delivering NewsArticles can be fed to C News in several ways.When a local user posts an article, the newsreader usuallyhands it to the inews command, which completes the header information.News from remote sites, be it asingle article or a whole batch, is given to the rnews command, which stores it in the/var/spool/news/in.coming directory, from where it will be picked up at a later time bynewsrun.With any of these two techniques, however, the article will eventually be handed to therelaynews command. For each article, the relaynews command first checks if the article has already been seen at the local siteby looking up the message ID in the history file.Duplicate articles are dropped.Then relaynewslooks at the Newsgroups: header line to find out if the local site requests articles from any of thesegroups.If it does, and the newsgroup is listed in the active file, relaynews tries to store the article inthe corresponding directory in the news spool area.If this directory does not exist, it is created.Thearticle's message ID is then logged to the history file.Otherwise, relaynews drops the article.Sometimes relaynews fails to store an incoming article because a group to which it has been posted isnot listed in your active file.In this case, the article is moved to the junk group.[1] relaynews alsochecks for stale or misdated articles and reject them.Incoming batches that fail for any other reason aremoved to /var/spool/news/in.coming/bad, and an error message is logged.After this, the article is relayed to all other sites that request news from these groups, using the transportspecified for each particular site.To make sure an article isn't sent to a site that has already seen it, eachdestination site is checked against the article's Path: header field, which contains the list of sites thearticle has traversed so far, written in the UUCP-style bang-path source-routing style described inChapter 17.If the destination site's name does not appear in this list, the article is sent to it.C News is commonly used to relay news between UUCP sites, although it is also possible to use it in anNNTP environment.To deliver news to a remote UUCP site, either in single articles or whole batches,uux is used to execute the rnews command on the remote site and feed the article or batch to it onstandard input.Refer to Chapter 16, for more information on UUCP.Batching is the term used to describe sending large bundles of individual articles all in one transmission.When batching is enabled for a given site, C News does not send any incoming article immediately;instead, it appends its path name to a file, usually called out.going/site/togo.Periodically, aprogram is executed from a crontab entry by the cron program, which reads this file and bundles all ofthe listed articles into one or more file, optionally compressing them and sending them to rnews at theremote site.[2]Figure 21-1 shows the news flow through relaynews.Articles may be relayed to the local site (denotedby ME), to a site named ponderosa via email, and a site named moria, for which batching is enabled.Figure 21-1.News flow through relaynews Notes[1] There may be a difference between the groups that exist at your site and those that your site iswilling to receive.For example, the subscription list might specify comp.all, which should send allnewsgroups below the comp hierarchy, but at your site you might not list several of the compnewsgroups in the active file.Articles posted to those groups will be moved to junk.[2] Note that this should be the crontab of news; file permissions will not be mangled.Prev Home NextHow Does Usenet Handle News? Installation[ Please note that the University of Edinburgh is not responsible for the content ofthese WWW pages.For queries please contact user@ph.ed.ac.uk whereuser appears after the ~ and before the / in the URL for this page ] Linux Network Administrators GuidePrev NextChapter 22.NNTP and thenntpd DaemonTable of ContentsThe NNTP ProtocolInstalling the NNTP ServerRestricting NNTP AccessNNTP Authorizationnntpd Interaction with C NewsNetwork News Transfer Protocol (NNTP) provides for a vastly different approach to news exchange from CNews and other news servers without native NNTP support.Rather than rely on a batch technology likeUUCP to transfer news articles between machines, it allows articles to be exchanged via an interactivenetwork connection
[ Pobierz całość w formacie PDF ]