DKIM Signing

[Matt Penfold]

I have set up DKIM signing on my postfix mail server. The DKIM records 
are correct, and amavis is loading the DKIM signing modules.

However amavis is not actually signing any outgoing emails.

50-user config:

use strict;
$enable_dkim_signing = 1;
dkim_key('tycornel.com', '2018', '/var/db/dkim/2018-tycornel-com.key.pem');
#------------ Do not modify anything below this line -------------
1;  # ensure a defined return


Postfix is sending outgoing mail to amavis for checking. I understand 
that by default amavis only checks mail sent from the localhost, but 
that is what is happening here:

postfix/submission/smtpd[1494]: connect from 
mail.dandderwen.uk[185.230.100.111]
postfix/submission/smtpd[1494]: DD49C1FEA8: 
client=mail.dandderwen.uk[185.230.100.111], sasl_method=PLAIN, 
sasl_username=matt at tycornel.com
postfix/cleanup[1495]: DD49C1FEA8: 
message-id=<20180511144207.6dbomfaiasbyhire at raspberrypi>
postfix/qmgr[852]: DD49C1FEA8: from=<matt at tycornel.com>, size=532, 
nrcpt=1 (queue active)
postfix/submission/smtpd[1494]: disconnect from 
mail.dandderwen.uk[185.230.100.111] ehlo=2 starttls=1 auth=1 mail=1 
rcpt=1 data=1 quit=1 commands=8
postfix/smtpd[1375]: connect from localhost[127.0.0.1]
postfix/smtpd[1375]: 6BB3A1FEA9: client=localhost[127.0.0.1]
postfix/cleanup[1495]: 6BB3A1FEA9: 
message-id=<20180511144207.6dbomfaiasbyhire at raspberrypi>
postfix/qmgr[852]: 6BB3A1FEA9: from=<matt at tycornel.com>, size=952, 
nrcpt=1 (queue active)
postfix/smtpd[1375]: disconnect from localhost[127.0.0.1] ehlo=1 mail=1 
rcpt=1 data=1 quit=1 commands=5
amavis[1210]: (01210-02) Passed CLEAN {RelayedInbound}, 
[185.230.100.111]:58352 [185.230.100.111] <matt at tycornel.com> -> 
<matt at dandderwen.com>, Queue-ID: DD49C1FEA8, Message-ID: 
<20180511144207.6dbomfaiasbyhire at raspberrypi>, mail_id: ZdpLv-OX_AQV, 
Hits: -1, size: 532, queued_as: 6BB3A1FEA9, 484 ms
postfix/lmtp[1496]: DD49C1FEA8: to=<matt at dandderwen.com>, 
relay=127.0.0.1[127.0.0.1]:10024, delay=0.77, 
delays=0.25/0.03/0.01/0.49, dsn=2.0.0, status=sent (250 2.0.0 from 
MTA(smtp:[127.0.0.1]:10025): 250 2.0.0 Ok: queued as 6BB3A1FEA9)
postfix/qmgr[852]: DD49C1FEA8: removed

Can anyone suggest why amavis is not signing emails?

Regards,

Matt Penfold