[Remops] EMP Filters and Me

[Bananasplit Admin]

On Fri, Mar 13, 2009 at 09:09:24PM -0400, drsnoid wrote:
> 
> Hi!
> I've been looking in to why my mail2news tests have been failing miserably
> the last few times I've sent them, and discovered that they are apparently
> being subjected to EMP filtering not only by the banana and mixmin
> mail2news, but by other forces unseen.  A perusal of
> <20090314000502.LPk9c0p7s9t7 at mail2news.mixmin.net> Mail2news Log 2009-3-13
> reveals many of the tests being rejected as duplicates.

I think you're referring to messages such as this:-
IHAVE to news-in.mixmin.net returned: 435 Duplicate

These aren't rejects, they are the news server advising that it already
has the message its being offered.  The mail2news gateway attempts to
deliver to a number of servers and sometimes the rate of propagation
between news servers is so high that the message is received at some of
them before the mail2news can inject it.  As an example:
mail2news.mixmin.net peers with news.glorb.com
mail2news.mixmin.net peers with news.mixmin.net
news.mixmin.net peers with news.glorb.com
Sometimes the mail2news sends a message to news.glorb.com and glorb forwards it
to news.mixmin.net faster than the mail2news can send it to
news.mixmin.net.  When the m2n tries to deliver to news.mixmin.net, the
news server already has the message and so it says, 435 Duplicate.

> Yes they are substantially the same message Subject and body and I can
> see why they they would be filtered if they were some sort of
> malicious spam or whatnot.  I'm not complaining or asking anybody to
> change anything, though would be grateful if you did!  I merely have a
> question:  Have the Remops en masse adopted some sort of EMP filter at
> the remailer exit level which had not existed previously?  How about
> the Dizum mail2news?  I'm getting similar failure with dizum but can't
> determine whether it's the exit remailer or the mail2news which is
> causing it.

Most, (not all) news servers run some kind of filtering to prevent spam
propagation.  Cleanfeed is the most popular such filter and by
default it will not reject EMP messages to test groups.  Were you to send
your messages to a non-test group, they would get rejected by an
EMP(phl) filter, (posting-host, lines).  i.e. Each post has the same
number of lines and comes from the same host.  Neither Mixmin or Banana
use this on test groups and I'm pretty sure Dizum doesn't.

> The mail2news situation really is in the toilet right now - there are
> basically 2 alternatives - Banana and Dizum.  Banana = banana, mixmin and
> for all intents and purposes Kulin.  Oh where did panta go?  He ran such a
> beautimous service!

Yes, the situation isn't good in terms of mail2news gateways at the
moment.  If anyone fancies running one, the code is freely available and
I'll happily peer with anyone, as I'm sure would Dizum.  Altopia is also
an excellent peer and has strong beliefs in such privacy services.

> Thanks for reading my blither.

'tis a pleasure.  :)

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