I've found that:
- submitted emails are signed properly (ie those sent with MUA's like Outlook and Thunderbird)
- command-line sent emails are signed properly
emails sent with PHP, in particular case PHPMailer (non-smtp submitted, ordinary PHP
mail()) are signed incorrectly.
I have heard about phpMailDomainSigner, which is kind of hack approach, and I would like to solve this at the top - MTA / milter level if possible.
# Log to syslog Syslog yes # Required to use local socket with MTAs that access the socket as a non- # privileged user (e.g. Postfix) #UMask 002 # dkim-milter (2.5.2.dfsg-1ubuntu1) hardy: # Disable new umask option by default (not needed since Ubuntu default # uses a TCP socket instead of a Unix socket). # Attempt to become the specified userid before starting operations. #UserID 105 # 'id postfix' in your shell Domain mysubdomain.domain.tld KeyFile /etc/mail/mail.private Selector mail # Common settings. See dkim-filter.conf(5) for more information. AutoRestart yes Background yes Canonicalization relaxed/relaxed DNSTimeout 5 Mode sv SignatureAlgorithm rsa-sha256 SubDomains no #UseASPDiscard no #Version rfc4871 X-Header no Statistics /var/log/dkim-filter/dkim-stats
/etc/postfix/main.cf (last lines of config file)
# DKIM milter_default_action = accept milter_protocol = 2 smtpd_milters = inet:localhost:8891 non_smtpd_milters = inet:localhost:8891