MS Exchange delivery notifications

Vernon Schryver
Sat Jan 25 21:56:57 UTC 2003

Judging from some samples, these MS Exchange delivery notifications
can be easily white-listed with a line in a whiteclnt file like this:

    ok      hex Fuz2: 52ac842b cf1d4ca8 206a0cbd 83eba349

Judging from the samples, my guess is that all MS Exchange notifications
will get that checksum from DCC client versions before 1.1.20 and
perhaps after 1.0.52.

However, the Fuz2 checksum of some MIME multipart messages including
these changed after version 1.1.20.  You should use this line in your
whitelist after 1.1.20:

    ok      hex Fuz2: 66e97088 bbb63c5a 400c04c5 55bde79a

That last is my point in this message.  If you are white-listing by
Fuz1 or Fuz2 hex checksum, it would be wise to check that the checksums
are the same after 1.1.20 and make any necessary changes.

It is safe to use both lines, because the chances of a collision
between a pair 128-bit hashes are about 1 in 10,000,000,000,000,000,000,
or probably less than the likelihood that your computer will mistakenly
decide that two differing checksums the the same.

The checksums of a message can be determined by feeding it to `dccproc -QC`.  

Vernon Schryver

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