| Alex de Joode 2004-10-25, 5:45 pm |
| lon <Anonymous-Remailer@see.comment.header> wrote:
[..]
: Anyway, things seem to have returned to normal since I had the
: problems mentioned above. I do have a related question, though.
: At times in the past I have noticed that posts on certain subject
: matter would not appear on Usenet even though sent multiple
: times using different remailers. Therefore, the situation could
: not have resulted from any particular remailer screening on
: content. So, I began to wonder whether screening/blocking
: could be taking place at the m2n level. I don't mean deliberately
: by the m2n operator, but as a sort of limited denial of service
: attack. Could an attacker with the right network access grab
: all the traffic bound for an m2n gateway and kill posts with
: certain keywords and allow the remainder of traffic to flow on
: to the gateway? That sort of capability could be more useful
: to an attacker/censor than doing a massive DoS attack and
: bringing down m2n gateways entirely.
I do not believe that an attacker can kill all post unnoticed.
This would mean all mail would have to go through a 3rd party
proxy before it is delivered at my mailserver (not likely).
The other option would be to kill the message when it arrives
at the newsservers. I peer (dizum) with 5 servers plus I peer
with my own newsserver (which again peers with 7 orso servers).
Killing the message their would basicly mean canceling the post,
that would leave a cancel message as trial.
As for filtering at the mail2news gateway, this unfortunately
is needed as spammers are trying to use the gateway to get access
to usenet. We therefore run a programme 'dupdetect' which checks
if a message scores high on the Breidbart Index. Duplicates get
killed. (http://www.stopspam.org/usenet/mmf/breidbart.html) Also
before a message is sent from the mailer to the mail2news gateway
spamassassin checks the message.
https://ssl.dizum.com/help/mail2news.html
Other things that can get your message killed:
Your message is larger than 24000
You post in html (Content-Type:.text/htm)
Adding a path header, (spoofing that is not allowed)
Crosspostings to more than 5 (five) newsgroups.
Setting Follow-up:, Approved: and Control: headers.
Hope this clarifies the process.
Cheers,
Alex
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