What is a shared IP pool?

A shared IP pool is a collection of outgoing IP addresses used by many customers of the same ESP. Reputation on these IPs rises or falls collectively. It is the communal dock where every arriving ship affects the reputation of the harbor.

The key risk is the noisy neighbor effect. If one sender abuses the pool, the entire IP can be blocklisted, damaging inbox placement for everyone. Most new senders begin in shared pools and must prove consistent, responsible behavior before qualifying for a dedicated IP.