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dkimsmimepostfix-mta
Niklas Riecken
Niklas Riecken

Reputation: 299

Email: DKIM Fails with S/MIME Signature

We have the following Mail Flow in our Company.

Exchange => ASSP => Postfix (DKIM Applies here) => CiperMail (S/MIME Applies here) => Internet

Now I face a problem, that as soon as I sign a Mail with S/MIME (Not encrypt - only sign), the DKIM Signature fails.

Why is that ? Any Idea, how to achieve having DKIM and S/MIME?

Regards, Niklas

Upvotes: 0

Views: 985

Answers (1)

Jörg Giencke
Jörg Giencke

Reputation: 21

1) THE PROBLEM

By applying S/MIME after DKIM you're changing the 'DKIMed' mail. Thus invalidating the hash.

2) THE SOLUTION

It should be done the other way round.

3) THE CLARIFICATION OF THE SOLUTION

The other way round means apply S/MIME first and then DKIM.

Upvotes: 1

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