I've documented my Proxmox cluster, switch connections, DHCP configuration, DNS zones, forwarding, and related network details. The remaining task is documenting every IP address, but I keep finding mistakes and second-guessing whether the information is accurate. Would combining DHCP leases, DNS records, Nmap scans such as -sV, and manual lookups provide a reliable inventory, or is there a better workflow and tool for establishing a baseline and keeping it updated?
4 Answers
Each method has blind spots: DHCP will not show statically assigned addresses, DNS may contain stale records or miss active hosts, and Nmap cannot see powered-off devices or systems blocked by firewalls. Use DHCP and DNS exports, ping or service scans, switch and virtualization data, and manual verification together, then review the differences against your IPAM database.
A practical workflow is to establish an initial baseline in a spreadsheet if that helps you organize the cleanup, then import the verified data into NetBox or another IPAM tool. Afterward, schedule discovery jobs and compare their results with the documented state. The goal is for scans to report unexpected or undocumented devices, not to replace the inventory itself.
The first complete inventory is usually the hardest part. After that, the important thing is assigning someone responsibility for maintaining it whenever equipment, users, subnets, or services change. Without that ongoing ownership, even a great inventory will become inaccurate again.
Use an IPAM system such as NetBox or phpIPAM as the source of truth instead of maintaining several spreadsheets. DHCP leases, DNS records, and network scans show different parts of the environment, so they should be treated as data sources that help you find discrepancies rather than lists you merge manually.
NetBox can feel more difficult at the beginning because you have to decide how to model sites, prefixes, devices, interfaces, and addresses. That setup pays off once the structure is established, especially if you automate imports instead of updating everything by hand.