DHCP failover database reconcile

Overview

Hot-standby or load-balance DHCP failover can drift after network partitions or buggy patches. Users get duplicates or ghost leases.

Symptoms

Conflict warnings, leases not freed, ICMP sweep shows address in use but DHCP thinks free.

Tooling

netsh dhcp server verify, Event ID 20292, compare scope statistics both nodes.

Reconcile steps (high level)

1. Export scopes both sides; identify mismatch epoch.
2. Follow Microsoft reconcile procedure for your mode—often pause partner, replicate, resume.
3. Afterward, verify exclusions and reservations synced.

Prevention

Monitor heartbeat alerts; stable time sync; avoid hand-editing one node only.

Comms

Wireless VLANs hurt loudest—schedule maintenance off-peak; have lease time short temporarily to accelerate healing with user impact understood.

Evidence

Save console exports for audit “we know who had which lease when.”