Thank you Till,
I now have the helo restrictions working. May I bug you once more to check the other ones for me? I think they are missing references to the virtual mail boxes except the client access. Could you advise me please, have I got this right or do I need to add some more references?
smtpd_helo_restrictions = permit_mynetworks, permit_sasl_authenticated, reject_non_fqdn_hostname, reject_invalid_hostname, permit
smtpd_sender_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_non_fqdn_sender, reject_unknown_sender_domain, permit
smtpd_recipient_restrictions = reject_unauth_pipelining, reject_non_fqdn_recipient, reject_unknown_recipient_domain, permit_mynetworks, permit_sasl_authenticated, reject_unauth_destination, reject_rbl_client cbl.abuseat.org, reject_rbl_client sbl-xbl.spamhaus.org, permit
smtpd_client_restrictions = permit_mynetworks, permit_sasl_authenticated, check_client_access mysql:/etc/postfix/mysql-virtual_client.cf
I appreciate your help and of course you patience.