I''m planning on implementing Domainkeys aka DKIM so that I can deliver mailing list messages to Yahoo and others. http://antispam.yahoo.com/domainkeys A Debian package would be nice, but I have not found one yet. Not sure if anything in DomainKeys would violate the Debian Social Contract or not. I don''t see anything in either http://apt-get.org/ http://backports.org/ My understanding so far is that recent Exim versions have DomainKeys support built in, although Exim does need an external encryptation library. I have found http://domainkeys.sourceforge.net/ http://www.kibibyte.se/download/debian/ The latter link seems to be the external encryptation library for Debian. Therefore, I may be able to build Exim with the EXPERIMENTAL_DOMAINKEYS option, and be up and running. I see a reference to exim4-daemon-custom which I assume helps me compile my own Exim underneath the Debian system. That''s the extent of my knowledge at the moment. If anybody has any clues, links, suggestions etc, I''m all ears. Thanks mark