ietf-nntp Response from ARTICLE

[Ned Freed]

> > What's the code for "you haven't issued a GROUP yet" ? That ought to be a
> > 5xx by the above logic. 4xx is reserved for "keep trying and it'll work
> > eventually".

> The code for "no GROUP selected" is 412, which does not agree with your
> interpretation. It is clearly no use repeating the ARTICLE command again
> later, because it will still fail. Likewise for "no current article
> selected" which returns 420. Both these cases imply a bug in your program.

I would agree that in these cases poor choices for codes have been made. This
is nothing new; there is at least one incorrect assignment of this sort in RFC
821.

I note in passing that 5xx codes appearing as 4xx codes are far less harmful
that 4xx codes appearing as 5xx codes. In the former case you get pointless
retries, in the latter case things fail that should eventually work.

Nevertheless, the theory of reply codes remains and is quite important
in many cases.

> Again, it the article requested is not found, the code returned is 430,
> but retrying later is unlikely to help if the cause was that the article
> requested had expired or been cancelled. It would only make sense to retry
> in the unliklely case where the article had not arrived yet (in which
> case, how had you come to learn of its message-id? - via some URL no
> perhaps).

You most certainly can learn of a message-id via a URL. Or a cross reference.

Such occurances are common in both email and news.

				Ned