Domainkeys and ISPs

[Michael Sprague <mfs@saneinc.net>]

Hi folks,

I'm setting up Domainkeys for my little ISP to help deal with the likes 
of Yahoo, AOL, Verizon, etc.  I have my outgoing server all setup to 
sign outgoing messages from our customers (well, at least the ones we 
host their DNS zone).  But, I don't believe that forwarded messages are 
being signed b/ the sender is not one of our customers (rather the 
original sender).

Since I'm new to the domainkeys thing, I'm not sure what is considered 
okay or not.  For example, I could sign every piece of email that leaves 
our outgoing server.  It seems pretty easy to do in exim4 by setting 
$dk_domain to whatever I want in the router.  But is that considered 
uncool?  Do other ISPs sign ALL messages to help deal with Yahoo?

Any insight is appreciated.

Thanks,
mikeS

--
Michael F. Sprague     | mfs@saneinc.net
http://www.saneinc.net | System and Network Engineering (SaNE), Inc
Providers of the SpamOnion anti-spam service