I notice that all signatures from Yahoo and Facebook are failing, and
mostly succeeding for other domains, including Gmail and Paypal. Not
that I care that much about validating email from Yahoo, but I wanted to
know if the problem was on my end, or their end. Surely Yahoo is
correctly signing their mail!?

So, I did some testing with the auto-responders listed in the
"Interoperability Testing" section of http://dkimproxy.sourceforge.net/

It appears that Yahoo's signatures fail for some of the autoresponders,
and succeed for others. Also, it appears the subsequent tests to the
same auto-responder yields inverse results.

Jesse

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Jesse Thompson
Division of Information Technology, University of Wisconsin-Madison
Email/IM: jesse.thompson@...