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3 .\" Copyright (c) 2019 Martijn van Duren <martijn@openbsd.org>
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17 .Dd $Mdocdate$
18 .Dt FILTER-DKIM 8
19 .Os
20 .Sh NAME
21 .Nm filter-dkim
22 .Nd add dkim signature to messages
23 .Sh SYNOPSIS
24 .Nm
25 .Op Fl a Ar algorithm
26 .Op Fl c Ar canonicalization
27 .Op Fl h Ar headers
28 .Fl d Ar domain
29 .Fl k Ar file
30 .Fl s Ar selector
31 .Sh DESCRIPTION
32 .Nm
33 adds a dkim signature to the message.
34 The following flags are supported:
35 .Bl -tag -width Ds
36 .It Fl a
37 The algorithm to use.
38 This implementation only supports rsa cryptography.
39 Only sha256 should be used for hashing, since other algorithms are most likely
40 not supported by verifiers.
41 Defaults to
42 .Ar rsa-sha256 .
43 .It Fl c
44 The canonicalization algorithm used to sign the messge.
45 Defaults to
46 .Ar simple/simple .
47 .It Fl d
48 The domain where the public key can be found.
49 .It Fl h
50 The email headers which are included in the mail signature.
51 Per RFC this option requires at least the from header to be included.
52 The headers are specified by separating them with a colon.
53 The default is
54 Ar from:reply-to:subject:date:to:cc:resent-date:resent-from:resent-to:resent-cc:in-reply-to:references:list-id:list-help:list-unsubscribe:list-subscribe:list-post:list-owner:list-archive .
55 .It Fl k
56 .Ar file
57 should point to a file containing the RSA private key to sign the messages.
58 .It Fl s
59 The selector within the _domainkey subdomain of
60 .Ar domain
61 where the public key can be found.
62 .El
63 .Sh SEE ALSO
64 .Xr smtpd 8