Understanding "Spam List = ..." mechanism

[Blaes, Rainer]

Dear experts,

the Mailscanner suite is running  under Solaris 7 with Virus detection
plus SpamAssasin feature
very well at our site.
To understand the philosophy behind the spam detection mechanism I would
like to ask if all the
servers from the Spam List (see below)  were contacted simultaneously or
only the first one then the
next server (if the first is not reachable)  or what else?

Spam List = spamhaus.org NJABL VISI Easynet-DNSBL Easynet-Proxies
Easynet-Dynablock Infinite-Monkeys

Many thanks in advance for the answer!

Rainer Blaes
EADS Space Transportation, Bremen (Germany)