markw@gvlf1-c.gvl.unisys.com (Mark H. Weber) (09/25/90)
After extensive investigation, I think I understand how the "Distribution: "
header is supposed to work in conjuction with the "Newsgroups: " header,
but I'd like someone to double check me.
In order for a news article to be received by a system, or sent to
the next system, there must be a matching entry in the "sys" file for
for both the "Newsgroups: " and "Distribution: " headers. An empty or
missing "Distribution: " header matches "world" in the sys file.
So far so good?
In Bnews, the Newgroups and Distributions are combined in the same field,
so that a site which wants a full mainstream news feed would have a sys
file entry something like this (I'm in Pennsylvania, USA):
mysite:comp,sci,rec,talk,news,soc,misc,world,na,usa,pa::
In Cnews this field can be separated into separate Newsgroups and
Distributions by use of a slash:
mysite:comp,sci,rec,talk,news,soc,misc/world,na,usa,pa::
or
mysite:comp,sci,rec,talk,news,soc,misc/all::
Am I still on the right track?
Where this starts to get weird (and I become less self-assured) is when
you get into the alternate and regional newsgroup hierarchies such as
"vmsnet", "ba", "ca" or (in my case) "pa". Many articles which are posted
to these groups have the hierarchy name in both the Newsgroup and
Distribution header. Therefore:
1) I assume that in Bnews, the same field in the sys file is scanned
twice for both headers, so that a single occurrence of the name
("pa" for example) matches both headers and allows these articles
to be propagated.
2) I further assume that Cnews works the same way as #1 above if the
field in the sys file has not been separated.
3) And finally, I assume that at Cnews sites where the fields have been
separated, the separate fields are scanned uniquely, and in order
for messages in the "pa" newsgroups which have been posted with "pa"
in both headers to be propagated, there must be a "pa" entry in both
fields, or a "pa" in the Newsgroups part, and an "all" in the
Distributions part of the field (or vice-versa).
Is this correct?
--
Mark H. Weber | Internet: markw@GVL.Unisys.COM
Unisys - Great Valley Labs | UUCP: ...!uunet!cbmvax!gvlv2!markw
Paoli, PA USA (215) 648-7111 | ...!psuvax1!burdvax!gvlv2!markwhenry@zoo.toronto.edu (Henry Spencer) (09/25/90)
In article <960@gvlv2.GVL.Unisys.COM> markw@GVL.Unisys.Com (Mark H. Weber) writes: > 3) And finally, I assume that at Cnews sites where the fields have been > separated, the separate fields are scanned uniquely, and in order > for messages in the "pa" newsgroups which have been posted with "pa" > in both headers to be propagated, there must be a "pa" entry in both > fields, or a "pa" in the Newsgroups part, and an "all" in the > Distributions part of the field (or vice-versa). Correct. -- TCP/IP: handling tomorrow's loads today| Henry Spencer at U of Toronto Zoology OSI: handling yesterday's loads someday| henry@zoo.toronto.edu utzoo!henry
markw@gvlf1-c.gvl.unisys.com (Mark H. Weber) (09/26/90)
In article <960@gvlv2.GVL.Unisys.COM> markw@GVL.Unisys.Com (Mark H. Weber) writes: >After extensive investigation, I think I understand how the "Distribution: " >header is supposed to work in conjuction with the "Newsgroups: " header, >but I'd like someone to double check me. Thanks to tale@cs.rpi.edu (David C Lawrence), who sent me an excellent summary of not only the mechanical quirks of the two headers, but also some of the current thinking on the subject. I think I'm up to speed now. Thanks, Mark -- Mark H. Weber | Internet: markw@GVL.Unisys.COM Unisys - Great Valley Labs | UUCP: ...!uunet!cbmvax!gvlv2!markw Paoli, PA USA (215) 648-7111 | ...!psuvax1!burdvax!gvlv2!markw