E. Allen Smith writes:
From: IN%"reece@taz.nceye.net" "Bryan Reece" 17-FEB-1997 23:23:10.06
use. However, I do have one problem with this recipe: lack of loop prevention if a news2mail gateway is going in the other direction.
All the mailing-list hosts are supposed to check for duplicates before forwarding anything, so this shouldn't do anything worse than have a few extra copies of each post get discarded, loading the network and the hosts a bit more. But posting the list to a widely-distributed
Umm... IIRC, the only person who's announced how he's filtering for duplicates is Igor, and he's just checking for messageIDs. Won't those get chunked on going through a mail2news gateway, and thus possibly come back through a news2mail gateway?
My script preserves the Message-ID, assuming that the incoming message has one. Other gateways I've seen also appear to preserve Message-ID lines (or at least messages posted through them appear to have mail-like ID lines).
The filtering mechanism could be improved via MD5 digests, etcetera (someone's already given a recipe for such; thank you), but even so various mungings could still set up a mailing loop. (Yes, I'm paranoid about those; I may have been reading list-managers for too long and seen too many stories on there.) The sensible place to keep track of possible duplicates is at the gateway; it can certainly filter based on that it (or, for that matter, another known bidirectional gateway) sent a message out.
Not immediately sending a message back to the host that it came from does look like a good idea (it came from foo.com, so foo.com obviously has it). Filtering out other gateways' messages will reduce load at the possible expense of delay (assuming a smallish network of news servers that feed each other the list; obviously the message will flood the majordomo net before it floods the real usenet unless something is seriously broken).
newsgroup seems wrong for noise (both to the list itself and to posters) and delay reasons.
Delay reasons being that mail will go to Usenet, go all over the place there, and then get replied to later than if it were just on the mailing list(s)? A potential problem, yes.
I didn't exactly say, but I was comparing a small network of news servers feeding each other cypherpunks.list to, say, alt.cypherpunks.list.
But (especially given the options I mentioned below), this would appear to be a matter for individual users to decide by which list they go with and any added control headers.
I'm trying to come up with a way to provide NNTP access (and an experimental alternative to the net-of-majordomos) that won't offend anybody too much. I can filter out messages that the authors don't want sent out; I'd prefer to deal with what would make the authors want the messages filtered out instead.
Maximum individual sovreignty (sp?).
In regards to your later query about whether people want their postings going to Usenet, might I suggest that this be individual to the given distributed mailing list? In other words, since the recipe is logically going to have to not forward to a gateway messages from other mailing lists (since it's not a good idea to have multiple copies of the same message arriving at the gateway if it can be helped; better to filter it out beforehand),
It doesn't seem an especially bad idea, since it
Thank you. Were you cut off?
Yes. Should have read: It doesn't seem an especially bad idea to send a gateway multiple copies of the same message, since theextra messages won't increase the load much but will increase the reliability and decrease the propagation time compared to a network where there are no duplicates. The only case where filtering duplicates is certain not to hurt delay or reliability is when the gateway in question is known to have a copy of the message already. Usenet uses the Path header for this; there doesn't seem to be such a thing in the majordomo net.
some of the mailing lists can forward and the others cannot. (One could even determine this behavior on application of the proper X-header, although I never trust various mailing systems to forward such intact.) The same could also be done with gatewaying _from_ Usenet - if the news2mail gateway feeds to whatever individual lists sign up to it and they _don't_ forward such messages to others, people can decide whether or not to receive Usenet postings on alt.cypherpunks.* by which list they subscribe to.
The code currently running is a perl script that turns typical email messages into something INN is happy with. It is probably possible to get your message rejected by INN if you put obsolete or otherwise unusual and illegal headers in. This may be a bug.
That would probably depend on: A. if any other circumstances other than deliberately sabotaging your message's translation would also disrupt its chances of getting through seriously, particularly if they weren't something you'd spot; and
The main way to get a message rejected seems to be using obsolete news headers on it. If you don't want your message posted, add a Posting-Version line to the header.
B. if sufficiently bad messages would disrupt INN's operations too much.
No more so than a sufficiently bad news posting that came in over NNTP (since the mails do turn into news postings over NNTP).