For DKIM :
http://www.iredmail.org/forum/topic232- … -dkim.html
For SPF, I think you just have to remove it in /etc/postfix/main.cf :
modify
smtpd_recipient_restrictions = reject_unknown_sender_domain, reject_unknown_recipient_domain, reject_non_fqdn_sender, reject_non_fqdn_recipient, reject_unlisted_recipient, permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination, reject_non_fqdn_helo_hostname, reject_invalid_helo_hostname, check_policy_service inet:127.0.0.1:10031
to
smtpd_recipient_restrictions = reject_unknown_sender_domain, reject_unknown_recipient_domain, reject_non_fqdn_sender, reject_non_fqdn_recipient, reject_unlisted_recipient, permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination, reject_non_fqdn_helo_hostname, reject_invalid_helo_hostname