Every cPanel account has a default mailbox. The main job of the default account is to deal with emails sent to non-existing email addresses. cPanel’s Default Address section lets you define exactly what should happen with such emails.
The default mailbox is created automatically when your cPanel account is set up, and the mailbox can’t be removed. This is because the mailbox does a number of important things.
For our example.net account we got just one proper email account: firstname.lastname@example.org. Assuming that the DNS is set up correctly emails sent to that email address will be delivered to our inbox. But what happens with emails that are sent to, say, email@example.com? By default, the email will be purged and the server will fire off a bounce email to the sender. There are other options though, as described below.
The same goes for emails sent from your website. By default, emails sent via for instance PHP scripts are sent from the default mailbox. In our case the emails would be sent from firstname.lastname@example.org. If a receiving mail server bounces one of our emails then the bounce email will be delivered to the default mailbox.
As an aside, if you are using the PHP mail() function then you should really sent email from a proper mailbox – relying on the default mailbox is likely to cause email delivery issues.
And to give one more example of the type of emails you may find in the default mailbox, by default cron job emails are also sent to the default account.
There are two common options for dealing with emails sent to non-existing users, as well as a few advanced options. The common options are:
Image: the Default Address interface lets you define how emails sent to non-existing users should be handled.
The default option (discard the email) is sensible. You are likely to find that pretty much all emails sent to non-existing users are spam, so you probably don’t want to forward the emails.
There are a few less common options for dealing with emails sent to the default mailbox. Clicking on the Advanced options link reveals them:
Image: the advanced options.
If you are hosting more than one domain (i.e. if you got one more addon domains) then you can configure how unrouted mail should be handled for individual domains. The default option is always to discard emails sent to non-existing email accounts. However, you can change this default for any individual domain:
In other words, you can choose to discard unrouted emails for example.net but forward unrouted emails for example.com. Again, we recommend to always use the discard option, but if you want you can change the default option.