How do ESPs manage IP pools?

ESPs maintain pools of sending IP addresses, allocating them to senders based on volume and reputation needs. Large pools allow distributing load, isolating problem senders, and maintaining reputation across different sender segments.

Shared IP pools group multiple senders on common addresses. Your reputation depends partly on pool neighbors' behavior. Dedicated IPs give you exclusive addresses where reputation reflects only your sending. Most ESPs offer both options at different price points.

Pool management includes: monitoring reputation across all IPs, rotating senders between addresses, isolating senders with delivery problems, warming new IPs gradually, and retiring addresses that develop poor reputation. Quality ESPs actively manage pools rather than letting problems spread.