Global MTA settings
i have enabled the following Global MTA settings:
TLS authentication only
Hostname in greeting violates RFC (reject_invalid_hostname)
Client must greet with a fully qualified hostname (reject_non_fqdn_hostname)
Sender address must be fully qualified (reject_non_fqdn_sender)
Client's IP address (reject_unknown_client)
Hostname in greeting (reject_unknown_hostname)
Sender's domain (reject_unknown_sender_domain)
If a messages is rejected by these is the sender informed & is there a log:confused:
Well, I'm not a Postfix expert, but I'll take a shot at giving you an answer since no one else has yet.
On your side these rejections should appear in the maillog file, which I believe resides in /var/log on most systems. Run a 'grep reject maillog' and you should see the rejections. Note that the rejection messages don't exactly match the settings here. For example, reject_unknown_sender_domain will show up in the log as something like "Sender address rejected: Domain not found". I believe you can change these messages within the Postfix configuration.
As far as whether or not the sender is notified I would answer "it depends". With these settings Postfix is going to drop the connection with the sending email server. In many cases the sending email server will bounce a message back to the original sender from the Mail Delivery Subsystem; at least this is the case with Sendmail and Postfix.
As I said, I'm not a Postfix expert so hopefully I haven't led you astray here, and if I have hopefully someone else will jump in and correct me.