This is dicey ESP bulk which SA will hardly ever detect.To help tag this you'll need to : - feed/use Bayes - implement Razor/Pyzor/DCC (if not already done) - write rules - header rules to score on certain X Headers, URI rules, etc. or track their IP ranges and reject at MTA level (would be my first choice) h2h Axb
Thanks for the tips. Will look into it.