Body Checksum Calculation

Vernon Schryver vjs@calcite.rhyolite.com
Mon Apr 1 17:16:54 UTC 2002


> From: Phil White <phil@itmagic.ltd.uk>

> DCC relies on the ability to recognise certain emails as bulk. However, it is 
> inevitable that some will sneak through. If I set up a dedicated email 
> address for other users to forward all email they regard as spam, will dcc 
> still calculate the checksums correctly?

If not, it's a bug.

If the question is about creating spam traps, see 

  - the last example in the dccproc man page in either the DCC source
     or http://www.rhyolite.com/anti-spam/dcc/dcc-tree/dccproc.html#EXAMPLES

  - the discussion of spam traps in the DCC installation instructions
      in the DCC source or in 
      http://www.rhyolite.com/anti-spam/dcc/dcc-tree/INSTALL.html#spam-traps

>                                          How many MUAs are known to reformat 
> messages, add line prefixes, headers, etc and will this break the dcc 
> mechanism?

No, because adding line prefixes is likely to change the "Body"
checksum, but usually not the "Fuz1" and "Fuz2" checksums.
All three of those checksums ignore whitespace.

> What methods do others here use?

The list of spam dictionary attack names can be used as spam traps
as mentioned on http://www.rhyolite.com/anti-spam/dict-attack.html

It is also possible to put spam traps on web pages and catch some
spam.  For example, look for aswwwblock in the source HTML for 
http://www.rhyolite.com/anti-spam/ 


Vernon Schryver    vjs@rhyolite.com



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