I installed and configured DKIM and DomainKeys milters for Sendmail by following the instructions from the following pages: http://www.elandsys.com/resources/sendmail/domainkeys.html http://www.elandsys.com/resources/sendmail/dkim.html The good thing is that I got these milters to sign all outgoing emails. However, the problem is that the signatures fail consistently for emails with a message larger than a certain size. For example, gmail says: dkim=neutral (body hash did not verify) For emails with a couple of sentences, the signatures always work as expected. I suspect that Sendmail is modifying the message in some manner after the email's been signed. I have Sendmail version 8.13.8 running on CentOS 5. I even tried using Postfix but with the same results. I would really appreciate some help here. Please let me know if I need to provide further information about my setup. Thank you very much!