John Kaufmann wrote:
> Nobody wrote:
>> This message was cancelled from within Mozilla Thunderbird.
>
> Interesting: Anyone know how this cancel <> function works?
Cancel works and doesn't work. Cancel is a form of control message.
On 'paper' - in theory - a news agent can send a cancel message to a
news server and the server will cancel (conditionally 'hide' rather than
delete) the message.
This condition can result in 'nefarious' misuse/abuse of the cancel
function in which 'anyone' could cancel anyone else's message/s.
Generic news agents such as Tb are designed to 'not allow' its user to
send such a cancel message for any message but those sent by its
originator - but such 'self-limitation' is not sufficient to prevent
abuse, so news servers have a variety of policies to prevent abuse.
A news server could 'honor' the cancel and 'pass it along' or propagate
it to other news servers. A news server could NOT honor, but pass it
along; and a news server could neither honor nor propagate a cancel message.
Another layer of complexity has been introduced to prevent abuse and
facilitate cancels, cancel-lock and cancel-key. This strategy allows a
server to only honor cancels by the 'owner' of the message (who is a
registrant of that server). News servers such as
news.individual.net
and eternal-september's employ that strategy.
In addition to cancel-locking, another cancel strategy is that of
'de-spammers' in which a news server gives special privileges to certain
message generators which allows them to cancel whose ever messages they
like as a method for removing spam news messages.
My understanding is that the giga news server which is
news.mozilla.org
only honors cancels in the form of 'expired' from certain elevated
moderator accounts.
--
Mike Easter