Re: Path header field

[Richard Clayton <richard@xxxxxxxxxxxxxx>]

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In message <JB7JBp.EtB@xxxxxxxxxxxxxxxx>, Charles Lindsey
<chl@xxxxxxxxxxxxxxxx> writes

>If Richard
>Clayton is listening, could he please repeat his reasons 

from June 2005, how time flies :(

>why the
><path-nodot> "demom" was needed (and is still used) by demon's servers,

What I said in http://www.imc.org/ietf-usefor/mail-archive/msg01381.html
was:

<quote>

It would also be unwise to put any existing servers in a position that
they found themselves feeling that to conform to modern standards they
should change their identity...

Demon Internet (the first UK dialup ISP in the early 1990s) has used
!demon! since before it was called Demon Internet or even before it sent
news over NNTP. When an error was made with a new peering machine and
this tag was omitted a number of customers (with simple single-user
"leaf" systems who only swapped articles with Demon) started fetching
articles and (trying to) re-inject them all. Because servers elsewhere
in the cluster, generally, already had a copy of the article this went
on unnoticed for weeks until occasionally the customer presented the
article earlier than the peering machine.... and when the article was
spam it tripped detectors and we found the problem.

What I'm trying to illustrate is that path identities are not only
important to the few thousand machines that peer news on a high volume
basis, but these identities are nailed into hundred of thousands of end
user systems. We outlaw (or deprecate) existing path identities, whether
dating from UUCP or more recent conventions, at our peril.

</quote>

what I'd add to that now is that any site with multiple machines doing
peering, handling injections etc is very likely to have its own custom
schemes for ensuring that databases are synchronised (or indeed there
may just be a central store of data). These are unlikely to depend on
scanning Path header fields, but of course they may.  However, when
articles depart from these systems to the rest of the world they'd like
to add a site-wide identity to show that they have been dealt with, so
as to discourage them being offered again. Hence the addition of
multiple path identities by such machines...

hence we see

        !newsfeed.gamma.ru!Gamma.RU!
        !supernews.com!corp.supernews.com
        !nx01.iad01.newshosting.com!newshosting.com
        !news.tele.dk!news.tele.dk!small.news.tele.dk

and doubtless many more (those were found in seconds in a current
feed...)

>and can we please then incporate that into the examples somewhere. 

I'm not sure it's to be encouraged for systems that are not so complex
as major peering hubs.  Mind you, I sometimes wonder if there's going to
be all that much left soon that isn't a major peering hub.

>The
>whole <path-nodot> business was heavily influenced by his example, but I
>forget the precise reasoning now.

- -- 
richard                                              Richard Clayton

They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety.         Benjamin Franklin

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