Below is a focused, practical guide to IP Address Management (IPAM) solutions suited for Internet Service Providers (ISPs) — covering commercial vendors, open-source options, key ISP requirements, pros/cons, and a short decision checklist.

Top commercial IPAM / DDI vendors (common in ISP / carrier environments)

• Infoblox (BloxOne / Infoblox IPAM)
  • Strengths: mature DDI stack (DNS, DHCP, IPAM), strong automation, discovery/asset visibility, multi-site/cloud support, vendor support and integrations for large deployments. Good for carriers that want turnkey DDI and vendor-managed scale. (Infoblox.com)
• BlueCat Integrity
  • Strengths: enterprise-grade IPAM + DNS/DHCP, good APIs and workflow automation, often chosen where flexibility and integration matter. Competitive with Infoblox on features and used by many large networks. (Peerspot.com)
• BT Diamond IP (and other carrier-focused products)
  • Strengths: products targeted at multi-site and large-scale IP estate management; often include advanced reporting and planning features for operators. (Peerspot.com)
• ManageEngine OpUtils and other mid-market DDI/IPAM tools
  • Strengths: lower cost, easier to deploy for smaller regional ISPs but fewer carrier-grade features. (Peerspot.com)

Open-source / building-block options (common for ISPs that want flexibility, lower license costs, or cloud-native deployments)

• NetBox (IPAM + DCIM)
  • Role: canonical source of truth for prefixes, VLANs, IP assignments, device interfaces. Excellent API and ecosystem (plugins, webhooks). Widely used by operators as the authoritative inventory. Good for multi-tenant models when extended. (GitHub.com)
• ISC Kea DHCP
  • Role: high-performance DHCP server used by many ISPs; can be integrated with NetBox or other orchestration via APIs. There are community and commercial editions (more runtime control in commercial). Integration projects (NetBox→Kea sync) are available. (GitHub.com)
• Combined approach: NetBox (IPAM) + Kea (DHCP) + BIND/PowerDNS (authoritative DNS) + orchestration (Ansible/Nornir) — common modular architecture for operators who prefer open stacks. Community tools exist to sync NetBox with Kea and with DNS engines. (GitHub.com)

Key ISP requirements to evaluate (these should drive vendor choice)

• Scale and performance: support for millions of IPs, high DHCP transaction rates, multi-site/global DNS. (Commercial DDI products are built for this; open-source stacks can scale but need engineering). (Infoblox.com)
• Multi-tenancy / customer isolation: per-customer views, role-based access, delegated administration and billing/chargeback integration.
• IPv4 + IPv6 parity: planning, allocation, discovery, reporting and automation for both protocols.
• Automation & API-first operation: REST/gRPC APIs, webhooks, event-driven syncs to provision DHCP/DNS from IPAM.
• Integration with OSS/BSS, NMS, orchestration (NetConf/RESTCONF, Ansible, Terraform, custom OSS/BSS hooks).
• Carrier features: CGNAT address pools tracking, DHCPv6-PD handling, delegated prefix management, large-scale DHCP failover and HA, and DNSSEC/RPKI workflows where applicable.
• Audit, reconciliation & discovery: automated discovery, conflict detection, reclamation workflows and reporting for audits.
• Support & vendor ecosystem: for 24x7 services, look for vendor SLAs, managed services or professional services to help scale.

Pros/cons summary (high level)

• Commercial DDI vendors (Infoblox, BlueCat, BT Diamond)
  • Pros: turnkey, tested at carrier scale, integrated DDI, vendor support, packaged HA and upgrades, enterprise integrations.
  • Cons: licensing cost, potential vendor lock-in, less flexibility to customize internal workflows.
  • Sources: vendor pages, industry comparisons. (Infoblox.com)
• Open-source component stack (NetBox + Kea + PowerDNS/BIND + custom automation)
  • Pros: lower license cost, full control, highly customizable, thriving ecosystems and connectors.
  • Cons: requires internal engineering to operate at carrier scale (HA, monitoring, backup, upgrades), potential higher operational overhead. (GitHub.com)

Recommendation / shortlist for ISPs

• If you want minimal ops overhead, predictable support and an integrated DDI product: evaluate Infoblox and BlueCat first (compare on pricing, deployments, and integrations with your OSS/BSS). (Infoblox.com)
• If you prefer lower license cost and want to own the stack (and have engineering resources): build a NetBox-centered workflow with Kea for DHCP and a DNS engine (PowerDNS/BIND) and use existing sync/connectors (there are community NetBox→Kea projects). (GitHub.com)
• For intermediary needs or limited budgets: consider ManageEngine/OpUtils or BT Diamond depending on feature fit and multi-site needs. (Peerspot.com)

Practical deployment checklist (quick)

1. Define scale targets: number of prefixes, IPs, DHCP transactions/sec, geographic sites, projected growth.
2. List required integrations: OSS/BSS, billing, NMS, orchestration tools, API contracts.
3. Must-have features: IPv6 PD, CGNAT pool tracking, multi-tenancy, RBAC, disaster recovery/HA.
4. Prototype: run a pilot importing current IP space and test reconciliation, DHCP integration, and failover behavior.
5. Measure operational load: staff time for upgrades, incident response, and custom development.
6. Compare TCO: license + hardware/cloud + staffing + professional services over 3–5 years.

If helpful, I can:

• produce a side-by-side comparison table (features vs. vendors) tailored to your scale and budget;
• help design a NetBox + Kea prototype architecture and list required components (HA, database, backups, monitoring);
• or give specific evaluation questions to ask Infoblox/BlueCat/BT during vendor RFPs.

Which of those would you like next (comparison table, NetBox prototype, or vendor RFP questions)?