Sign up ×
Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

I'm running email sending campaigns with milions of emails, and I need to sign each and one of them with DKIM. Unfortunately that's the bottleneck of the process.

I wonder if I can calculate a DKIM signature ONCE and use it in all of the mails (maybe only signing the subject, that is common to the whole campaign).

Is that possible?

share|improve this question

1 Answer 1

Yes this is possible but defeats the reason of using DKIM. It is intended to sign each of the mails separately! Otherwise I can sign mails that look like your mails. With any content I like to use as long as it has the same subject.

If you need more speed, buy new hardware. What about a computing cluster? Or drop DKIM at all as you seem not to care about signing your mails.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.