CSCatchAll adds a much-needed feature to MS Exchange Server 2000 and 2003: A catch-all mailbox that receives all mail originally addressed to recipients that are not in your active directory. There is zero configuration of CSCatchAll necessary - just install it and add a "catchall@yourdomain.com" E-Mail-Adresse address to any of your users in the active directory. That user then receives all misaddressed E-Mail-Adresse.
This feature is very useful if you do not want to emit non-delivery reports back to the sender and still want to keep your normal E-Mail-Adresse addresses. CSCatchAll only reroutes those emails that can not be matched to any regular recipient in your organization.