darrell@drux3.UUCP (09/16/83)
We are running version 2.10.1 of the netnews software here at AT&T
Information Systems Labs in Denver. According to the manual page for
postnews you are allowed to enter a distribution which can restrict
the locations to which a news item is submitted. In Mark Horton's
"How to Read the Network News" it states that you can specify any
newsgroup class you want it distributed to. I assume that if I post
an article I want distributed to just netnews sites in Colorado there
would have to be a newsgroup class name 'co' (or something similar)
that the Colorado sites would have to subscribe to. Is this correct?
Would the article still be posted to the groups specified in
newsgroups but limited to only those sites which receive 'co'? I
haven't been able to find any documentation which gives details on the
distribution line.
Thanks in advance.
Darrell McIntosh, AT&T Information Systems Labs, Denver
{ihnp4|hogpc}!drux3!darrell (303)538-3212mark@cbosgd.UUCP (09/17/83)
Distribution works like this: Whenever netnews has to make a decision about which neighbors to forward an article to, normally that decision is based on the newsgroups of the article and some pattern for each neighbor saying which newsgroups go to that neighbor. For example, you might have mysys:net,fa,oh,cb:: cbsys:net,fa,oh,cb:: ohsys:net,fa,oh:: njsys:net,fa:: in your sys file. This means your system "mysys" has three neighbors, one also in Columbus (for this example, I'll assyme mysys is in Columbus) called cbsys, one in Cleveland called ohsys, and one in New Jersey. There are newsgroup classes net and fa that we all know, oh that goes only within ohio, cb that goes only within Columbus, and local newsgroups that don't go anywhere. (Many systems have "net.all" instead of "net", and so on for other newsgroup classes. It means almost exactly the same thing.) If an article were in Newsgroups: net.wanted it would go to everywhere class "net" goes, e.g. everywhere. If it were in Newsgroups: net.wanted,cb.general it would still go everywhere, but get read by both subscribers of net.wanted all over the world, and cb.general here in Columbus. If it's posted to Newsgroups: oh.general it goes to cbsys and ohsys, but not njsys, and will (presumably) eventually make it to only Ohio sites, to be read by subscribers to oh.general. Now, all Distribution does is provide a substitute for Newsgroups when the forwarding decision is made. Thus Newsgroups: net.wanted Distribution: oh.general causes the article to be sent to all sites that would get oh.general (e.g. all Ohio sites) but NOT to the net at large. However, it is read by Ohio subscribers to net.wanted, not (necessarily) by the subscribers of oh.general. In other words, when inews is trying to decide whether to forward article A to neighboring system S, the code essentially does if A has a Distribution line then let D be the contents of the Distribution line else let D be the contents of the Newsgroups line if system S subscribes to any newsgroup in D then transmit A to S Now, there's a subtlety here. It seems silly (as a user interface issue) to specify Distribution: oh.general when you really want to just restrict the distribution to Ohio - that is, why should you have to pick a valid newsgroup matching oh.all? The answer is you don't have to - nothing checks that the Distribution is a valid newsgroup. All it really is is a string that has to match the pattern in the sys file. So you can just say Distribution: oh and it works fine, IF your sys file says things like ohsys:net,fa,oh:: If your sys file looks like ohsys:net.all,fa.all,oh.all:: the string "oh" won't match "oh.all", and it won't get transmitted. As it turns out, this is the only difference between "foo" and "foo.all" in a newsgroup pattern - the former matches "foo" and "foo." followed by anything - the latter requires the dot and something after it. Since we're about to create usa and na newsgroup classes, I recommend that all netnews administrators immediately take the following action. In your sys file, delete all occurrences of the string ".all". This will help out the distribution mechanism, and also makes your sys file shorter and easier to read and maintain. While you're at it, add "na,usa,mod," to the list of classes - na goes to all sites in North America, usa goes to all sites in the USA, and mod goes everywhere (same as net and fa). Mark Horton
bees@druxy.UUCP (09/19/83)
By the way... according to someone at another colorado site
(of which we have no uucp connections to any of them!), there
is a series of 'co' newsgroups.
Lets get some local uucp connections, Darrell!
Ray Davis AT&T Information Systems Labs @ Denver (303)538-3991
{ihnp4|hogpc}!druxy!bees