This document discusses techniques for detecting compromised machines ("zombies") that are involved in spamming activities on a network. It proposes using heuristic search and message partitioning/replication to minimize spam access from zombies while ensuring data confidentiality and integrity. Zombies are controlled by botnet herders and use various techniques to send large volumes of spam while remaining untraceable, such as exploiting vulnerabilities on Windows systems to use infected machines as mail relays or sending spam from dynamic IP addresses. The document analyzes spam sent from different IPs to examine the extent to which spam originates from a small number of hosts.