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From: eggert@twinsun.com (Paul Eggert)
Newsgroups: news.software.nntp,news.software.b
Subject: Re: NNTPD hates Message-IDs with TWO '@'s in them.
Message-ID: <1991Jun15.212751.1558@twinsun.com>
Date: 15 Jun 91 21:27:51 GMT
References: <1991Jun9.232828.17956@europa.asd.contel.com> <5930@gazette.bcm.tmc.edu> <1991Jun13.043253.20660@zoo.toronto.edu> <6014@gazette.bcm.tmc.edu>
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sob@tmc.edu (Stan Barber) writes:

>As I read RFC1036, it follows RFC822/1123 for all headers defined in
>those documents and sets standards for those headers not defined in
>RFC822/1123. To me, that means that a Date field that does not conform to
>RFC823/1123, it is illegal. You and Geoff seem to agree with that. Now,
>we have Messages IDs that don't conform and you say that that is ok
>despite what RFC822/1123 say.

C News needn't discard _incoming_ articles with nonconforming
Message-IDs; it is allowed to, but it doesn't have to.  However, it
must _generate_ articles with conforming Message-IDs.

Unfortunately, C News's policy of passing through headers unaltered
means that, if it wants to conform to the RFCs, it must check that
incoming headers strictly conform to the RFCs before passing them
through to the next news host.  Instead of ``be generous in what you
accept and strict in what you produce'', C News must be strict in what
it accepts because it mustn't pass through bad headers.

In practice, C News isn't this strict, accepts and passes through
mistakes like Message-IDs with two `@'s, and therefore doesn't conform
strictly with the RFCs.  I suspect there are several reasons for this:

	The RFCs are too complicated.

	Making C News strict would cause even more of an uproar than
	the recently added loose header checking.

	Being strict would make C News a little less efficient.

	Which is more important, obeying the RFCs precisely, or
	transporting news effectively?

The lessons for NNTPD should be clear (:-).