In reference to the following page: http://dkimproxy.sourceforge.net/postfix-outbound-howto.html
it includes the following: submission inet n - n - - smtpd -o smtpd_etrn_restrictions=reject -o smtpd_sasl_auth_enable=yes -o content_filter=dksign:[127.0.0.1]:10027 -o receive_override_options=no_address_mappings -o smtpd_recipient_restrictions=permit_mynetworks,permit_sasl_authenticated,reject however I do not send emails from my desktop using port 587, I use port 25 as standard. How could I include the line "-o content_filter=dksign:[127.0.0.1]:10027" in a manner where only OUTBOUND emails only are passed through DKIM proxy, and not incoming emails? Yes, I am well aware that SMTP does not draw a distinction between the 2, but I am thinking there must be a way, or do I have to send emails via a port other then 25 to achieve this? On this topic has anyone found a good DKIM signing solution that will work with multiple domains?