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[DOC] NoCeM - What you need to know

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Sep 2, 2023, 6:15:35 PM9/2/23
Contents :
1 - Preamble
2 - Definition of NoCeM
3 - NoCeM or Cancel?
4 - Nocem issuers
5 - Descriptions and tips on existing nocems
6 - Conclusion
7 - References

1 - Preamble

This document, posted monthly, list the nocems currently published
on the "news.lists.filters" group.
It does not deal with nocems published in a local hierarchy.
The aim is to publicize existing general nocems so that server
administrators can decide which nocems they wish to apply or not.

2 - Definition

NoCeM (pronounced No See 'Em) is a modern solution for managing spam.

Rather than issuing a "cancel" on a spam message that most servers will
reject, we generate a message in the "news.lists.filters" group called
"nocem", which contain the message(s) to be deleted.

Each nocem is signed with a gpg key to guarantee its authenticity.

The manager of each server is free to apply these nocems or not,
unlike global cancels, nothing is imposed.

3 - NoCeM or Cancel?

- Using nocems requires the server administrator to modify its configuration
to accept them. Otherwise, the nocem does nothing on the server.
It's a simple text message.

- Cancel, on the other hand, is accepted by default by the server
configuration. It's up to the server administrator to modify his config
to refuse certain types of cancels. This is not always easy.

For example, the server refuses cancels from miakibot
because of past abuse. But the server configuration had to be modified
for this. Servers with little administration or little knowledge of "fr"
specificities generally keep the default config.

Reminder: general NoCeMs are published in news.lists.filters.

4 - Nocem issuers

- " bleachbot " ( : The oldest and best-known

- " nocembot " ( : The latest bot

- " nono le petit robot " ( : The atypical robot using

- " NoCeM ALPHANET big8 " ( : nocems.

5 - Descriptions et conseils sur les nocems existants

5.1 - " bleachbot "

Information :

Public key :

Types of nocems :
- spam : detection based on previously confirmed spam with BI>=20.
- site : flood and hipcrime detection.

Tip: Nocem has been a recognized source for years.
Recommended for use on all servers.

5.2 - " nocembot "

Information :

Public key :

Types of nocems :
- spam : spams and clearly malicious articles
- flood : well-known regular flooders

Tip: New public Nocems source since June 5, 2023
(previously restricted to the server).
The website details what is filtered.
Recommended for use on all servers.

5.3 - " nono le petit robot "

Information :

Public key :

Types of nocems :
- spam : spams 99,99%
- spam2 : spams with rare false positives
- spam3 : spam with false positives
- spam4 : spams with slightly more false positives
- site : rare manual notices

Tip: these nocems are the result of the use of "spamassasin".
An effective product usually used to detect spam in e-mails.
Type "spam" nocems are reliable, the others generate false positives.
Particularly spam3 and 4, which on certain forums such as fr.soc.politique
could be seen as censorship.
The "site" nocem is used for abuse that is generally consensual.
Recommended use of "site" and "spam" nocems on all servers

5.4 - " NoCeM ALPHANET big8 "

Information :;a=blob;f=alphanet/nocem-types

Public key :;a=blob_plain;f=usenet/abus/d/NoCeM/pubkey/all;hb=HEAD

Types of nocems:
- spam : spam on big8 groups.

New, more or less curious types of nocems are published
(non-exhaustive list):
- cleanfeed-emp
- cleanfeed-too-many-newsgroups
- cleanfeed-binary-non-binary-distribution
- cleanfeed-hierarchy-violation--crosspost-outside-netscape
- cleanfeed-post-to-junk-newsgroup
- cleanfeed-hierarchy-violation--crosspost-outside-sdnet
- cleanfeed-bot-signature
- cleanfeed-hierarchy-violation--crosspost-outside-de.alt.dateien
note: many types of nocems (against mashed potatoes, ducks etc.) are only
published on a french-speaking group and outside the scope of this document.
Tip: As they stand, we strongly advise against using these nocems
because their content does not always correspond to the description
of this type of nocem.

For example, the SPAM type confuses "spam" with "flood".
or this nocem cancels a flood post
from a well-known flooder: " Socratis T.n.p".
There's also " Pentcho Valev ", " Lucrezio S " etc

6 - Conclusion

If you want to contribute to this document, you can reply directly
to this message (or by e-mail if you prefer).

7 - References:
- The NoCeM FAQ. V0.93:
- Kleopatra:
(certificate manager and GUI for GnuP)
- Global cancels: <>

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