How do I manage the reputation of multiple IPs/domains?

Each IP and domain requires individual monitoring. Use Google Postmaster Tools, Microsoft SNDS, and Yahoo Complaint Feedback Loop to track reputation signals for every sending identity. Don't assume good performance on one means all are healthy.

Segment traffic strategically. Assign specific IPs and domains to distinct email streams based on risk profile and importance. High-value transactional mail should flow through your most protected infrastructure; experimental campaigns can use separate, more expendable resources.

Maintain sufficient volume on each. Splitting traffic too thin leaves IPs and domains without enough data to establish stable reputation. If you can't sustain the volume, consolidate rather than letting resources go cold.

A captain inspects every ship in the fleet. The flagship may gleam while a cargo vessel takes on water.