> > Conceptually DKIM needs to go over the email twice: once to calculate
> > and sign the checksum and once to write it out with the result of the
> > previous step in the headers.¹
>
> Prepending a header does not require rewriting the message body.
> Postfix queue files support efficient
> > So far I see that the after-queue content filter mechanism
> > (FILTER_README) forces you to write the email to disc again. (And
> > for no good reason, unfortunately: pipe should pass a read-only
> > file descriptor of the queue file to filter?s stdin. The filter
> > can use lseek() on that.)
can’t do that? Or can it? How?
Regards,
Robert
> Gesendet: Samstag, 15. Januar 2022 um 20:16 Uhr
> Von: "Bob Proulx"
> An: postfix-users@postfix.org
> Betreff: Re: How to filter email (DKIM) without keeping the message in memory
> and without writing it to disc twice
Hello everyone,
I need to DKIM sign possibly huge emails (up to 150MB).
Conceptually DKIM needs to go over the email twice: once to calculate and sign
the checksum and once to write it out with the result of the previous step in
the headers.¹
A DKIM signer can do this by either keeping the
