For Catch All accounts follow the link.

https://support.google.com/a/answer/33962?hl=en

To create a catch-all address for delivering messages addressed to non-existent recipients:

  1. Sign in to the Google Admin console.
  2. Click Google Apps > Gmail > User settingsWhere is it?
  3. (Free edition) In the Catch-all address section, select the Forward the mail to: radio button. (Other editions) In theEmail routing section, select the Route to catch-all address: radio button.
  4. Enter the user name to which mail addressed to unknown users will be forwarded. The user name must be a valid account in your domain. Do not include the domain name; Google Apps automatically adds @your-domain to the address.
  5. Click Save changes.

To bounce messages addressed to non-existent recipients:

  1. Sign in to the Google Admin console.
  2. Click Google Apps > Gmail > User settingsWhere is it?
  3. (Free edition) In the Catch-all address section, select the Discard radio button. (Other editions) In the Email routingsection, select the Discard radio button.
  4. Click Save changes.