What is a phased migration strategy for moving to a new IP/domain?

Phased migration approach:

Phase 1: Setup

Configure new IP/domain with authentication

Test deliverability before migration

Verify everything works

Phase 2: Split traffic

Send small percentage through new infrastructure

Most engaged segments first

Monitor both old and new closely

Phase 3: Gradual shift

Increase new infrastructure percentage

Decrease old infrastructure usage

Continue monitoring throughout

Phase 4: Completion

All traffic on new infrastructure

Old infrastructure deprecated

Full monitoring continues

Allows rollback if issues discovered.

Gradual fleet transition. New ships prove themselves before old ones retire.