OT mail spam question

Vintage> I just moved my mail server to my internal office network. Vintage> The IP block I've been assigned apparently used to be used Vintage> for dynamic DSL users. The problem is, at some point Vintage> someone used one or more of these IP addresses to send out Vintage> spam, enough so that my entire Class C block is blacklisted Vintage> in some database. Vintage> I'm getting reject messages occasionally when I try to send Vintage> someone e-mail, like so: Vintage> ----- Transcript of session follows ----- ... while talking Vintage> to smtp.secureserver.net.: Vintage> <<< 553 66.120.4.* mail rejected due to excessive spam (Spam Vintage> received from 66.120.4.201) 550 5.1.1 Vintage> &lt;mike(a)sccpc.com&gt;om>... User unknown Vintage> It's a very small percentage of my mail, but it's keeping me Vintage> from responding to people sending me inquiries in some Vintage> instances. Vintage> How the *hell* do I track down what fuckwit is blacklisting Vintage> my address? That won't necessarily help. Some of these blocker "services" are run by selfrighteous zealots who think that some spam messages from an ISP customer is sufficient grounds to blacklist ALL mail from ALL customers of that ISP. And they don't seem to be amenable to reason. The best solution is not to communicate by people who support such fools; once they switch to more sensible spam prevention tools, they'll be able to communicate again. paul