RE: sample SigningTable and KeyTable files

From: Murray S. Kucherawy <>
Date: Mon, 29 Nov 2010 08:31:37 -0800

> -----Original Message-----
> From: [] On Behalf Of R.A. Imhoff
> Sent: Monday, November 29, 2010 5:11 AM
> To:
> Subject: sample SigningTable and KeyTable files
> Hello,
> would anybody be able to send me a sample of what a valid SigningTable
> and KeyTable looks like?

There's some documentation for them in the opendkim/README with examples, as well as a general description in the opendkim.conf(5) man page for both.

> This is for Ubuntu 10.04 with Postfix hosting multiple virtual domains,
> and the goal would be to enable DKIM signing of all outgoing mail from
> these different domains -- since Postfix doesn't differentiate which
> virtual host sends out mail with which "From" header, they can all use
> the same key file.
> The downside is that any virtual domain can impersonate a sender on one
> of the other domains on the same server, but I don't see how to prevent
> this for mail being sent out from php scripts, even with different key
> files for each domain, and in any case in the present setup the domains
> are all administered by the same person.

Your PHP scripts could generate an additional header field specific to the domain that's generating the mail, and opendkim could be told to use that header field to determine the sender instead of the From: field. Check out the "--enable-sender_header" option to ./configure and the corresponding SenderHeader item in opendkim.conf(5).

> (In case any of the developers come across this: it would really be a
> useful addition to the documentation to give some examples ...)

If the documentation in opendkim/README not sufficient, let us know... or you could send us some documentation that works for you once you've sorted it out and we could include it in future releases.

Received on Mon Nov 29 2010 - 16:31:47 PST

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