'empty' messages

Vernon Schryver vjs@calcite.rhyolite.com
Mon Sep 19 15:15:53 UTC 2005

> From: Pavel Urban <pavel.urban@ct.cz>

> I'm receiving user complaints about empty messages marked as spam by 
> dcc. Some people in our company routinely send messages with just 
> Subject: and 'empty' body. I've tried to add a rule for the most common 
> destination, but it obviously doesn't work. Is there a way to whitelist 
> this kind of traffic? Thanks!

Are the messages really empty or do they consist of empty MIME attachements
as in the spam you sent?  Such empty MIME attachements are difficult
to whitelist by body checksum because they consist mostly of random
MIME boundary strings.  If they really are empty, they can be whitelisted
with John Levine's list of empty and test body checksums.  That can
be fetched automatically into /var/dcc/testmsg-whitelist with
/var/dcc/libexec/fetch-testmsg-whitelist run by cron.
It should be used by including it in /var/dcc/whiteclnt:

  include testmsg-whitelist

> ok      env_to  postmaster
>          env_to  postmaster@iol.cz
>          env_to  abuse@iol.cz
>          env_to  tech@iol.cz

In what way do those whitelist entries not work?  They should exempt
mail sent to those mailboxes from DCC checks.

Do you trust your local users to never send evil spam?  If so,
could you whitelist your local IP addresses, perhaps with

    ok  ip
    ok  ip

Vernon Schryver    vjs@rhyolite.com

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