There are several ways you can block inbound emails from being processed by Postmark. The benefits of blocking an inbound message are that your application doesn't need to process it and so it doesn’t count toward your monthly usage. A common reason for blocking an inbound message is because of spam or abuse targeted at your inbound address.
Blocked inbound messages have a retention of 10 days before being deleted.
Postmark performs a scan on each inbound message and assigns a spam score in the X-Spam-Score header. By setting a spam threshold, Postmark will block all inbound messages that have a spam score higher than the set threshold.
When logged into Postmark, select the server and go to the Inbound message stream. Then select "Settings" and the “SpamAssassin threshold” slider is where you can set your desired value.
You can modify the InboundSpamThreshold field using the Servers API to modify existing servers. You can also use the Servers API to create servers and set the InboundSpamThreshold field at the same time.
You can also block individual email addresses or domains. By creating a sender rule, Postmark will scan each inbound message to your Postmark server and block any messages that match the rule.
When logged into Postmark, select the server and go to the “Settings” tab. Then select the “Inbound” tab and the “Inbound rules” section is where you can manage this.
You can manage your Inbound rules through the Triggers API.
Email messages that are blocked by any of the inbound rules are not processed by Postmark's servers. Bypassing easily allows you to process a message that was once blocked.
When logged into Postmark, select the server, then stream and go to the activity. Any blocked messages will have a “Bypass” button that will manually process the email.
You can bypass an individual message by using the Messages API.
