Safeguard 1.4: Use Dynamic Host Configuration Protocol (DHCP) Logging to Update Enterprise Asset Inventory

Safeguard 1.4 requires you to ingest DHCP lease logs and use them to keep your enterprise asset inventory current, so newly connected and transient devices are discovered quickly and recorded with accountable ownership. Operationalize it by centralizing DHCP logs, parsing them into asset records, reconciling duplicates, and creating an exceptions path for networks that do not use DHCP. ¹

Key takeaways:

• DHCP logs are a discovery feed; your asset inventory is the system of record that must be updated from that feed. ¹
• You need a documented runbook: log sources, ingestion method, reconciliation rules, and an exceptions process for non-DHCP segments. ¹
• Evidence must prove continuous operation: log retention, successful ingestion, inventory updates, and remediation tickets for gaps. ¹

A workable asset inventory fails in predictable places: unmanaged laptops that appear for a day, lab systems, BYOD, contractor endpoints, and “temporary” VLANs that become permanent. DHCP is one of the few sources that sees many of those assets at first contact because it records lease requests and assignments on networks where devices obtain IP addresses dynamically. Safeguard 1.4 turns DHCP into a repeatable discovery mechanism and ties it to your asset inventory maintenance process. ¹

For a Compliance Officer, CCO, or GRC lead, the goal is not to become a DHCP expert. The goal is to make this requirement auditable: clear ownership, a defined operating cadence, and evidence that DHCP logs actually drive inventory updates. That means you need (1) complete DHCP log coverage for in-scope networks, (2) a consistent way to ingest and normalize lease events, (3) decision rules for what becomes an “enterprise asset,” and (4) an exceptions register for networks where DHCP logs are not available or not meaningful (static IP ranges, OT segments, certain cloud networks). ¹

Requirement: safeguard 1.4: use dynamic host configuration protocol (dhcp) logging to update enterprise asset inventory requirement

Plain-English interpretation: Collect DHCP lease logs from the DHCP services you run (or consume), centralize them, and use them to add or update assets in your enterprise asset inventory so the inventory reflects what actually connects to your networks. ¹

Control intent: Reduce “unknown device” exposure by making asset discovery continuous, not episodic (for example, not only during quarterly scans). DHCP provides near-real-time signals for many endpoint classes and helps identify rogue, unmanaged, or newly introduced assets. ¹

Who it applies to

Entity scope: Enterprises, service organizations, and technology organizations implementing CIS Controls v8. ¹

Operational scope (where this matters most):

• Corporate networks where endpoints receive addresses via DHCP (wired, wireless, guest with internal reachability, branch networks).
• Datacenter VLANs that still assign IPs dynamically for certain tiers (VDI pools, ephemeral test environments).
• Hybrid environments where DHCP is split across Windows DHCP, network appliances, and IPAM platforms.

Common out-of-scope (but must be explicitly treated as exceptions):

• Static IP subnets (servers, network gear, OT) where DHCP logs do not represent the population.
• Cloud-native networks where instances are not assigned via your enterprise DHCP service.

The audit problem is rarely “we don’t have DHCP.” It’s “we have DHCP logs somewhere, but they don’t reliably update the inventory, and no one can prove coverage.”

Regulatory text

Excerpt provided: “CIS Controls v8 safeguard 1.4 implementation expectation (Use Dynamic Host Configuration Protocol (DHCP) Logging to Update Enterprise Asset Inventory).” ¹

Operator meaning: You must implement a repeatable mechanism where DHCP logs are:

1. captured and retained,
2. centrally reviewed or processed, and
3. used to create/update asset inventory entries.

A policy that says “we maintain an inventory” is not enough. You need an operating process that shows DHCP events flow into inventory maintenance, with evidence.

What you actually need to do (step-by-step)

1) Define the control card (so it’s runnable)

Create a one-page “requirement control card” with:

• Owner: usually IT Infrastructure or Network Engineering; GRC owner: oversight and evidence QA.
• In-scope DHCP sources: Windows DHCP, Infoblox/IPAM, router/switch DHCP services, Wi-Fi controller DHCP relay visibility, etc.
• Trigger/cadence: continuous ingestion, plus a recurring reconciliation review.
• Output: updated enterprise asset inventory entries and exception tickets.

If you run Daydream for GRC operations, this is where you turn the requirement into an assignable control with tasks, evidence slots, and an exceptions workflow that doesn’t get lost in email.

2) Inventory the DHCP log sources (coverage map)

Build a “DHCP coverage map” table:

Network / site	DHCP service	Log location	Centralized to SIEM?	In asset scope?	Notes

Your goal: every in-scope network has a declared DHCP log source, or a documented exception with compensating discovery (see below).

3) Centralize and retain DHCP logs

Minimum operational expectation:

• Configure DHCP servers/services to emit logs at a consistent level (include MAC, hostname, IP, lease start/end, and interface/VLAN where possible).
• Forward logs to a central log platform (often SIEM or log pipeline).
• Set retention aligned to your internal security logging standard (if you don’t have one, define it and apply it consistently).

Auditors will test whether logs exist, whether they’re complete, and whether you can retrieve them for a given timeframe. Missing retention decisions create rework later.

4) Parse DHCP lease events into normalized asset signals

Define a normalization spec (even a short one) that maps DHCP fields to your asset inventory fields:

• Unique identifiers: MAC address is common; hostname is helpful but untrusted; IP is ephemeral.
• Timestamps: first seen, last seen from DHCP perspective.
• Network context: site/VLAN/SSID, if available, to support scoping and triage.

Then implement parsing:

• Option A: SIEM rules create “asset discovery” events.
• Option B: Log pipeline (ETL) writes into CMDB/asset platform.
• Option C: IPAM tool is the source, exporting to asset inventory.

5) Reconcile DHCP-discovered devices to existing inventory

You need deterministic matching rules. Example decision logic:

• If MAC matches an existing asset record, update last-seen and current IP details.
• If MAC is new, create a provisional asset record with a status like “unattributed” pending ownership assignment.
• If hostname changes frequently, do not treat hostname as authoritative; store it as an observed attribute.

Create a triage queue for “new asset sightings”:

• Assign to IT Asset Management or Endpoint team to validate ownership, managed status, and required security controls (EDR, disk encryption, MDM).
• Require closure codes: legitimate new corporate asset, third-party device approved, guest/isolated, rogue/unapproved, false positive.

6) Build an exceptions path for non-DHCP and blind spots

Document exceptions by network segment, not by vague statements. Common exception categories:

• Static IP server networks (compensate with cloud inventory, hypervisor inventory, or authenticated scanning).
• OT/ICS networks (compensate with passive network monitoring approved for OT).
• Cloud VPCs/VNETs without DHCP logs under your control (compensate with cloud provider asset inventory exports).

Each exception should have:

• Scope, owner, compensating control, and review cadence.
• Evidence that the compensating control runs.

7) Prove it operates: recurring health checks

Run a recurring control health check that answers:

• Are all declared DHCP sources still forwarding logs?
• Are there ingestion failures?
• Are new devices being created/updated in the inventory as expected?
• Are “unattributed” assets being resolved within your internal SLA?

Track findings to closure with tickets and timestamps.

Required evidence and artifacts to retain

Keep an “evidence bundle” that a third party (auditor/customer) can validate without reverse engineering your environment:

1. Control card / runbook (owner, scope, cadence, exception rules).
2. DHCP coverage map (networks → DHCP sources → logging destination).
3. Configuration proof (screenshots/exports) showing DHCP logging enabled and forwarding configured (redact secrets).
4. Log samples from centralized platform showing required fields (MAC, IP, timestamp, hostname if present).
5. Inventory update proof:
   • Change records from CMDB/asset tool (created/updated assets tied to DHCP sightings), or
   • Reports showing “first seen/last seen” updates derived from DHCP events.
6. Reconciliation and triage records: ticket queue exports, closure notes, and exception approvals.
7. Health check reports: ingestion monitoring alerts, weekly/monthly check sign-offs, remediation tickets.

Daydream can help by templating the evidence bundle per run cycle so you always collect the same artifacts, in the same place, with an approver trail.

Common exam/audit questions and hangups

• “Show me that DHCP logs update the inventory, not just that logs exist.” Be ready with before/after asset records tied to a DHCP event.
• “What networks are covered?” Provide the DHCP coverage map and list explicit exceptions.
• “How do you prevent duplicates?” Explain MAC-based matching, plus dedupe logic for multi-NIC devices and docked laptops.
• “How do you handle guest/BYOD?” Show segmentation and whether those assets are excluded by design or inventoried as a separate class.
• “Who reviews the queue of new devices?” Name the team, show the ticket workflow, and show closures.

Frequent implementation mistakes (and how to avoid them)

1. Logging exists, ingestion is broken.
   Avoidance: Monitor log-forwarder health and set alerting on “no DHCP events in last X hours” per site.

2. No authoritative matching key.
   Avoidance: Use MAC as the primary key where possible; store hostname as observed data; record multiple MACs per device when needed (Wi-Fi and Ethernet).

3. Treating DHCP as complete asset discovery.
   Avoidance: Document compensating discovery for static and cloud segments; auditors accept coverage with explicit scope and controls.

4. No ownership assignment process.
   Avoidance: New sightings must land in a triage queue with required closure codes and an accountable resolver.

5. Evidence is scattered.
   Avoidance: Define a minimum evidence bundle and a single retention location with access controls.

Enforcement context and risk implications

No public enforcement cases were provided for this specific safeguard in the supplied sources. Practically, failure modes show up as: unknown devices on internal networks, incomplete incident scoping (you can’t answer “what is this IP?” quickly), and gaps in downstream controls that depend on inventory (vulnerability scanning coverage, EDR coverage, patch compliance).

Practical 30/60/90-day execution plan

Days 0–30: Establish coverage and data flow

• Assign control owner(s) and publish the control card/runbook.
• Build the DHCP coverage map; identify missing sites, rogue DHCP services, and undocumented segments.
• Turn on DHCP logging where absent and forward logs to the central platform.
• Define the normalization spec (fields, keys, retention location for evidence).

Days 31–60: Automate updates and triage

• Implement parsing and ingestion into the asset inventory or an intermediate asset staging table.
• Create matching/deduplication rules and test against real DHCP data (expect messy hostnames).
• Stand up the “new asset sightings” triage queue with ticketing and closure codes.
• Draft the exceptions register for non-DHCP segments with compensating controls and owners.

Days 61–90: Operationalize, measure, and audit-proof

• Run the first control health checks; capture failures as tickets and remediate.
• Produce an evidence bundle from one full operating cycle (logs → ingestion → inventory changes → triage closures).
• Conduct an internal “audit-style” walkthrough: pick several IPs/MACs from DHCP logs and trace them into the inventory and ownership records.
• Formalize ongoing cadence and assign backup owners.

Frequently Asked Questions

Do we have to add every DHCP client to the enterprise asset inventory?

You need defined rules for what becomes an inventory record versus a transient observation. Many teams create provisional records for new MACs and then classify them (corporate, third party, guest, rogue) through triage. ¹

What if we use static IPs for servers and network devices?

Document those segments as exceptions and point to compensating discovery (CMDB imports, cloud inventory, network management systems, or authenticated scans). Auditors mainly want explicit scope and proof the compensating process runs.

Our DHCP is split across Windows DHCP and an IPAM appliance. Is that acceptable?

Yes, as long as you centralize logs (or exports) from both and apply consistent parsing and reconciliation into a single inventory view. Your evidence should show coverage across both sources. ¹

How do we prevent duplicates when a laptop has Wi‑Fi and Ethernet MAC addresses?

Store multiple interfaces per asset and implement correlation rules (for example, tie interfaces to a single device record through endpoint management identifiers). If you can’t correlate automatically, route to triage with a “merge candidates” queue.

What about DHCP relay. Do we need logs from relays or only from the DHCP server?

The requirement is about DHCP logging that supports inventory updates; the cleanest source is typically the DHCP server/service logs. If relay metadata is needed to determine site/VLAN, capture it where feasible and document how you enrich events. ¹

How do we show auditors that this control runs continuously?

Keep time-stamped ingestion/forwarding health evidence, periodic health check sign-offs, and examples of assets created/updated across different dates. Pair that with a runbook that defines cadence and ownership. ¹

Footnotes

1. CIS Controls v8