Email::MIME w/ Mail::DKIM::Signer?

[SteveTheTechie]

I am the current developer for the FreeToastHost website system, used by over 10,000 Toastmasters clubs worldwide.

The system successfully employs Email::Simple, Email::MIME, and Email::Sender.

Our mail system is essentially an email forwarding and distribution list system. We convert system provided email addresses sent through the email handler code on the server to actual email addresses that users enter via the web interface and are stored in our MySQL database.

Unfortunately, because some email distribution lists are to non-club members, we require the insertion of unsubscribe links at the bottom of the mail bodies to protect the server's email reputation. We are successfully using walk_parts from Email::MIME to accomplish that.

However, here is the catch. Altering the emails like this requires that we delete DKIM headers from the incoming email since they would be invalid. Also, we have to make sure the FROM header consistently reflects our server address. Consequentially, sending the outgoing email without the DKIM headers has gradually led to a drop in our deliverability over time. We have occasional problems with MS-Hotmail/Outlook, for example, and have to instruct our users to white list us which they do not like.

I am looking to create new DKIM headers for the outgoing mail. We have the DNS records set up for this.

I ran across Mail::DKIM::Signer, apparently by another author. At first glance, it looks like it requires a message format (line termination codes) that might be incompatible with Email::MIME.

Do you know if there are any incompatibilities between the two? Do you have any experience using the two modules together? (I will be ask the same question to the author of Mail::DKIM::Signer.)