I have a catchall account, so I get quite a bit of spam. Spamassassin correctly junks most of them. But I'm seeing that many of the spam keep using the same non-existing recipient (i.e. webpage@example.com, etc.).

When signing up with some services, I created throwaway accounts, so I need to keep a catchall.

How do I have a catchall account and *reject* those emails sent to non-existing accounts? I want those to be rejected to avoid backscatter and not even need to reach Spamassassin to process.

ZCS 5.0.7-64bit + CentOS 5.2