I would like to set up a DKIM record for outgoing emails from a forums server running on Ubuntu, but need to figure out how to do it. This is a non-standard server (e.g. not Postfix, not SendMail, not Exchange, not a cPanel setting, no PHP is involved, not WordPress). In particular, I'm not using Ubuntu's email system. I'm using the SMTP server in my own forums software.
I am able to modify the server code to add extra email headers as needed, but have been unable to figure out all the pieces required in searching.
From what I've read here and there, I understand I need a public key and a private key, but there are details I don’t understand.
- I used a key generator I found in a Google search to generate DKIM public and private keys for the domain. Does it matter which key generator I use to obtain the public and private keys?
- I need to add a DKIM header to the outgoing mail headers. I can add headers to my outgoing mails, but I don’t know the format of this header.
- I need to add at least one TXT record to the DNS, but I don’t know the format for a DKIM record. In this case a sub-domain will be sending the email.
- I think, but am not sure, that I need to have the public or private key readable somewhere on my server for validation. Is that so? That part is completely vague to me.
Can someone answer these points. I believe if I understand what the generic pieces are I can put them together, unless specialized software is required to manage the DKIM record.