Blacklist all incoming email except for a few whitelisted addresses

[StoneyCreeker]

I have a client that gets massive amounts of spam daily. Spamassassin is blocking over 700 a day but many are getting through still. I have his setting at 2. It was catching 80-90% until around September, then the spammers apparently started using new techniques to get past spamassassin with low scores.

He has started a new g*ail account, (let them filter it instead of me ), but I need to keep his current email account active as it has thousands of critical emails sorted in IMAP folders. I do not want any new spam emails to this account and I want to blacklist all incoming mail except for a few addresses. (like me)

Can I use "account level filtering" in CPanel, ie "From" "contains" "*.*" "Discard Message", with the allowed addresses in rules above it, or should I use spamassassin to blacklist *@* and then allow 3 whitelisted addresses?

I thought about creating an EXIM filter but I don't know how to isolate those rules to just one account. My cpanel_exim_system_filter_custom is at 98kb with rules and it works great across all my domains. I just can't keep up with all the new spam, just the most used ones. "Whack a mole" is never ending .

Thank You!

 

[cPanelMichael]

Hello

Have you considered using BoxTrapper? It's documented here:

cPanel - BoxTrapper

BoxTrapper filters spam from your inbox through challenge-response verification. When an account that has BoxTrapper enabled receives an email, BoxTrapper automatically sends a verification email in response. The sender must complete the verification process before the email can pass to your inbox. If the sender does not verify the email, the verification fails and BoxTrapper never clears the message for delivery. After a period of time, the system automatically deletes the spam.

Thank you.

 

[StoneyCreeker]

Thanks for the suggestion.
I had disabled it in Tweak Settings years ago. It is ok for a personal account but creates problems with a commercial account.

Boxtrapper may be the answer. It does look like a lot of manual labor when a simple rule might take care of it automatically.

I am compiling BoxTrapper white list entries.
He is on many automatic mailing lists that will not respond to boxtrapper's request.
I guess I'll have to log into his IMAP account and go through the emails.
He does not have the time to do this himself.
Looks like a long day...

 

[cPanelMichael]

Feel free to let us know if it works out as a viable solution.

Thank you.