Domainkeys support is now implemented in the stock Exim distribution.
Just download the latest Exim version and build it with the EXPERIMENTAL_DOMAINKEYS option as outlined in the "experimental features" documentation (available in the Exim tarball).
So is Yahoo going to start blocking email if I don't build domainkeys in?
Heck I already see numerous emails sitting in the queue with @yahoo.com addresses...
So what happens to those people who have a domain and yet because of their ISP blocking port 25 (Yahoo??) cannot send email using their domains smtp? So they try to send through their ISPs smtp but want (and really should be able) to use their domain's return email address?
It is a good idea but there is no one answer. The system from it's foundation is broke and needs a complete rework.
I do not like Yahoo nor AOLs implementation of their spam controls. They take the options away from their users and in addition to that try to force the rest of the world to conform to them...hmm...sounds like that little company I've driven by up in Redmond!
Have a great 4th everyone!