DDI (DNS/DHCP/IPAM): what to consider before design
DDI is tier-0 infrastructure: a DNS, DHCP or IPAM failure often means service outages or uncontrolled network changes. Be clear before proposing ownership, source of truth and operating rules.
DNS, DHCP and IPAM are the basic building blocks of the infrastructure.
If the ownership, source of truth and process of change are not clear,
even a small error can cause a widespread outage.
The minimum standard is an authoritative IPAM, controlled changes, response quality monitoring and tested recovery.
Key questions
- Ownership: who is the owner of DNS/DHCP/IPAM and who approves changes (change process, windows, rollback)?
- Source of truth: where is the authoritative record of addresses, subnets, reservations and names (IPAM vs. tables)?
- Availability: what is the availability goal and what does the real HA model look like (failover tests, not just "two servers")?
- DNS design: internal vs. external zones, split-horizon, forwarders, delegations and nomenclature rules.
- DHCP design: scope strategy, reservations, relay, conflict detection and outage procedures.
- Integrations: how changes are made - manually or via API/IaC; who handles automation and change auditing.
- Monitoring: what we monitor (service, latency, responses, saturation, error rate), not just VM health.
- Recovery: configuration backups + recovery test (how quickly we can recover and who will do it).
- Security: access rights, segmentation, hardening, audit logs and protection against "shadow DNS".
Practical first steps
Begin by defining source of truth (IPAM), change process and minimal monitoring (availability and response quality). Only then address migrations, consolidation and automation.
DDI is not about a specific product. It's about making changes controlled, operations predictable and incidents resolvable without improvisation.