Richard,
richards@waikato.ac.nz (Richard L Shepherd) writes:
>
> I have this problem where nntpcache (NNTPcache server V2.3.2.1 on Linux)
> will return the CORRECT values to a LISTGROUP command but not to an XOVER
> command.
>
> Readers such as tin and ANU news (Vaxen) do not see the problem - I assume
> they use LISTGROUP and then HEADER <num> on each number output by
> LISTGROUP which will always give you valid headers.
>
> However netscape, freeagent, krn (and others I'd bet) all use XOVER (I
> believe) and, indeed, when I telnet to the server on port 119 I get bogus
> results from XOVER. Consequently these newsreaders give a list of
> headers, some of which just report "Bad article number" when you attempt
> to read them. This is bad and looks bad. It seems that expire/resync is
> not happening even though I "kill -USR[12]" the process to attempt to
> force the issue.
What I think the problem is.
The results of xovers are (normally) cached in disk files. When
processing an xover from a newsclient
- those cached xover-lines which are within the current "active range"
of articles are fetched
- holes in the obtained list are requested from the remote news server
and the returned lines are added to the xover file
- the fetched cached lines and the lines from the news server are
returned to the newsclient
Therefore expiring of the xover files does not matter.
I think the missing articles are canceled articles. When the xover of an
article is cached and the article is canceled afterwards, an xover line
for this article will be sent until it falls out of the active range
of articles.
This is inherent to caching. But is indeed ugly. A possible solution
would be to do a LISTGROUP from the remote server before each xover
and ignoring cached xovers that correspond to missing
articles. Evidently there should not be any caching of the results
from the LISTGROUP command.
I think this solution would not waste too much bandwidth.
Cheers,
Hugo
Hugo Embrechts
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