How can I have an email account only accept whitelisted senders?
I have an email address that gets so much spam that I had to stop using it entirely, but I'm wondering if there's an application or method I can use to still accept mail to that address, but only from a specific sender. I happened to use the address in question to sign up for my AdSense account, and Google won't allow me to change it to a new address (at least last time I asked). I only want to affect this certain address in this way, not the others I have under the same domain (the other addresses don't get much spam since I'm very cautious with them now, so they don't need any filters that might accidently lose legitimate mail).
My dedicated server is running FreeBSD 4.10, and I use DirectAdmin 1.23.3 as a control panel (DA is able to blacklist and whitelist addresses with Spamassassin, though as best I can tell, doing so affects the mail for the entire domain, which won't work for my situation I think).
So anyhow... if there's a good way I can accomplish this, either with just some system tweaks or installing an application, that'd be great. Thanks in advance for your advice.