How to protect remaining healthy IPs or subdomains?

Protecting unaffected sending assets:

Strict traffic separation:

Do not route problem segments through healthy IPs

Do not mix affected domains with clean ones

Keep transactional isolated from marketing

Monitor actively:

Watch healthy assets for any reputation decline

Check postmaster tools daily

Alert on any metric changes

Preventive measures:

Reduce volume even on healthy streams

Focus on highest-quality segments

Avoid any experimental sends

Contingency planning:

Have backup sending ready

Know how to reroute quickly if needed

Healthy infrastructure is valuable. Protect it from contamination.

Keep clean ships away from damaged ones. Prevent spreading the problem.