spammer using cancel evading technique

Russ Allbery rra at
Thu Dec 4 02:42:54 UTC 2003

Tomasz R Surmacz <tsurmacz at> writes:
> Russ Allbery wrote on Tue, Dec 02, 2003 at 06:18:03PM -0800:

>> Yup, you can definitely do that in a local Perl or Python filter and
>> it's not a bad idea for inclusion in something like Cleanfeed.

> But due to the efficiency reasons, wouldn't it be better to include it
> in actual innd C code?  So far, this is not a big problem, as such
> pseudo-cancels are not common yet, but I bet they will spread if we do
> not take some action.

This is about the most efficient sort of check one could do; I don't think
you'd really notice the difference.  About the only speed hit you're
incurring is the creation of the Perl header hash.  I'm hesitant to
include things like this into the C code because it's hard to change the C
code, and this is fundamentally a site policy decision (there isn't
anything special about <cancel.*> message IDs in the specification).

Russ Allbery (rra at             <>

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