qdkim will be discussed on the openqmail mailing list.

qdkim is a module to verify DKIM signatures of incoming messages as well signing outgoing messages. It is available as part of openqmail. It is designed to incorporate with eQmail, but should work with other *qmail derivatives in general too.

Download the sources and extract it. Change into the source folder  qdkim  and check the file  conf-home . Then run

$ ./configure
$ make
$ make install

All pathes below are relative to the eQmail home directory. The main config file is  etc/qdkim.conf . After installation it consists working defaults. DKIM processing is deactivated (OFF) by default.

Before messages can be signed a domain key is required. To create one for  example.com  run

$ mkdkimkey example.com

An existing key will not overwritten. The key have to be published in DNS. To check out the TXT record for bind use the  -p  option:

$ mkdkimkey -p example.com

Publish the key in DNS. Keys will be stored in  etc/dkimkeys/<domain>/  with dropped access rights. Now put  qmail-sdkim  include the full path on the first line of  etc/beforemote  ^*, e.g.

/var/qmail/bin/qmail-sdkim

Last step is to activate signing in the config file by setting

DOSIGN=1

Now you can test it:

$ echo "DKIM test" | sendmail -f user@example.com <your@email.address>

The recommended way to plugin  qmail-vdkim  is to set

QMAILQUEUE=/var/qmail/bin/qmail-vdkim

Afterwards a restart is required. To activate verification set in  etc/qdkim.conf 

DOVRFY=1

The mentioned file  etc/beforemote  is part of  qmail-bfrmt , a feature of eQmail which is usually not available on derivatives. Workaround:

After qdkim was installed, stop *qmail and do

$ mv qmail-remote qmail-remote.bin
$ ln -s qmail-sdkim qmail-remote

In qdkim.conf set QMAILREMOTE to the renamed  qmail-remote.bin  with the correct absolute path, like

QMAILREMOTE="/usr/local/qmail/bin/qmail-remote.bin"

Refer to Configuration above and start *qmail.

There is a patch available also. Use at your own risk.