Was sad to learn that Smartermail, as used by my ISP v13.2, does not allow domain-level whitelisting or blacklisting - strongly recommend this be added to the next version.
That said, perhaps someone knows of another way to accomplish the same end goal:
Our ISP hosts 20 email accounts for our company (shared host).
Spam is killing us, 80k+ spam messages per month.
Began using SpamArrest a few years ago (our MX record points to them) - up until recently, this worked great.
Spammers have now taken to sending their trash directly to our domain, bypassing SpamArrest.
Could fix if we could whitelist the five IP's that SpamArrest forwards our mail from (Blacklist everything else).
BUT, not an option since SmarterMail only allows server-level white/black listing.
Only other option that comes to mind is paying for a full VPS to host our email - perhaps someone here knows of other, more reasonable options...
Thanks - John G