Further to our earlier annoucement Bounce Spam Blocking we have updated the way this is handled after feedback from a number of customers.

The customers who are largely affected by bounce backs are those using catch-all accounts. As these accept mail to anything on the domain wether the user account is used or not.

So we have created a sophisticated rule on the server that only accepts mail where the sender is null when the account actually exists.

For instance if the email account mail@domain.com was a catch-all account then mail sent with a blank sender (bounced mail) to mail@domain.com would be accepted. However mail sent to user@domain.com with a blank sender would be rejected. But all other mail would be delivered to mail@domain.com.

This change means that customers who want to receive bounce backs and delivery notifications are able to do so while the risk to catch-all email accounts of receiving masses of rejected mail is reduced.

It is important to point out though that not all bounced mail is sent with a blank sender. In this case these messages may get through.

If you find your catch-all mail account becoming full with rejection notifications on a continual basis then it is likely your domain has been harvested and is being spoofed by spammers. In this instance we highly recommend removing the catch-allaccount and setting up secific forwarding accounts for each email address you require.