Each VDS account is automatically setup with a default POP3 email account with the same username as your VDS. 

Bounced messages will be delivered to this POP account.

For example, if your VDS username is "bob123", you will have a POP3 account by the same name "bob123" with the email address, of course, being bob123@yourdomain.com and mail can be retrieved with the same password you use to login to your control panel.

Remember that your login for your email client software (Outlook, Outlook Express, Thunderbird, etc) for accounts with shared IP addresses use the bob123%yourdomain.com login name unlike the unique IP address accounts that only use the "bob123" id to login.