windows_exporter/internal/collector/dhcp/AGENTS.md

dhcp collector

The server metrics come from the single-instance PDH object DHCP Server, read with pdh.CounterTypeRaw. It exists only where the DHCP Server role is installed. These notes were recorded on Windows Server 2025 (build 26100) with a DHCP server that served no clients.

• Every .../sec counter is PERF_COUNTER_COUNTER. Its raw value is a cumulative count since the DHCP service started; publish it as a counter.
• PERF_COUNTER_RAWCOUNT counters, by help text:
  • Gauges: Active Queue Length, Conflict Check Queue Length, Offer Queue Length (packets in a queue) and Failover: BndUpd pending in outbound queue.
  • Cumulative: Denied due to match., Denied due to nonmatch., Failover: BndUpd Dropped. and the three Failover: Transitions to ... state. counters.
  • Milliseconds per packet (Avg). (not read) is an average in milliseconds, not paired with a base.
• Many counter names end in a period, and some failover names in /sec.. The perfdata tags must keep it.
• Only Packets Received/sec was nonzero on the recording host.

Counter reference

Recorded on Windows Server 2025 (build 26100). Raw and Base are the first and second values that pdh.CounterTypeRaw returns for the sample instance.

DHCP Server

Single-instance.

Counters the collector reads:

Counter	Type	Raw	Base
Acks/sec	PERF_COUNTER_COUNTER	0
Active Queue Length	PERF_COUNTER_RAWCOUNT	0
Conflict Check Queue Length	PERF_COUNTER_RAWCOUNT	0
Declines/sec	PERF_COUNTER_COUNTER	0
Denied due to match.	PERF_COUNTER_RAWCOUNT	0
Denied due to nonmatch.	PERF_COUNTER_RAWCOUNT	0
Discovers/sec	PERF_COUNTER_COUNTER	0
Duplicates Dropped/sec	PERF_COUNTER_COUNTER	0
Failover: BndAck received/sec.	PERF_COUNTER_COUNTER	0
Failover: BndAck sent/sec.	PERF_COUNTER_COUNTER	0
Failover: BndUpd Dropped.	PERF_COUNTER_RAWCOUNT	0
Failover: BndUpd pending in outbound queue.	PERF_COUNTER_RAWCOUNT	0
Failover: BndUpd received/sec.	PERF_COUNTER_COUNTER	0
Failover: BndUpd sent/sec.	PERF_COUNTER_COUNTER	0
Failover: Transitions to COMMUNICATION-INTERRUPTED state.	PERF_COUNTER_RAWCOUNT	0
Failover: Transitions to PARTNER-DOWN state.	PERF_COUNTER_RAWCOUNT	0
Failover: Transitions to RECOVER state.	PERF_COUNTER_RAWCOUNT	0
Informs/sec	PERF_COUNTER_COUNTER	0
Nacks/sec	PERF_COUNTER_COUNTER	0
Offer Queue Length	PERF_COUNTER_RAWCOUNT	0
Offers/sec	PERF_COUNTER_COUNTER	0
Packets Expired/sec	PERF_COUNTER_COUNTER	0
Packets Received/sec	PERF_COUNTER_COUNTER	59
Releases/sec	PERF_COUNTER_COUNTER	0
Requests/sec	PERF_COUNTER_COUNTER	0

Not read by the collector:

• PERF_COUNTER_RAWCOUNT: Milliseconds per packet (Avg).