Overview¶

The Exchange Online probe monitors a Microsoft 365 tenant's Exchange Online service through the Microsoft 365 reporting and Graph APIs, providing mail-flow volumes, mailbox counts and storage, service-health status, and tenant reachability. Authentication uses an Azure AD app registration (client credentials); no user account or password is stored. One probe instance monitors one tenant; add more instances for additional tenants.

Collected data:

Tenant reachability (did the reporting API answer this cycle)
Exchange service-health status, per reported service
Mail flow over the reporting window: messages sent, received, delivered and failed
Mailbox counts (total and active)
Aggregate mailbox storage consumed, in bytes
Mailboxes over their warning quota

All metrics are emitted under the senhub.exchange_online.* namespace. Mail-flow metrics are cumulative counters over the reporting window; mailbox storage is reported in bytes.

Quick Start¶

Basic Configuration¶

# probes.d/40-exchange-online.yaml — each file under probes.d/ is a YAML array of probes
- name: exchange-online-prod
  type: exchange_online
  params:
    tenant_id: "00000000-0000-0000-0000-000000000000"
    client_id: "11111111-1111-1111-1111-111111111111"
    client_secret: "${secret:exchange-online.client_secret}"   # OS secret store; inline plaintext is auto-sealed on install
    interval: 300

The ${secret:...} reference resolves the client secret from the OS-native secret store (see Configuration). tenant_id and client_id identify the Azure AD tenant and the app registration used for authentication.

Multiple Tenants¶

Monitor several tenants with separate probe instances:

# probes.d/40-exchange-online.yaml
- name: exchange-online-contoso
  type: exchange_online
  params:
    tenant_id: "00000000-0000-0000-0000-000000000000"
    client_id: "11111111-1111-1111-1111-111111111111"
    client_secret: "${secret:exchange-online-contoso.client_secret}"
    interval: 300

- name: exchange-online-fabrikam
  type: exchange_online
  params:
    tenant_id: "22222222-2222-2222-2222-222222222222"
    client_id: "33333333-3333-3333-3333-333333333333"
    client_secret: "${secret:exchange-online-fabrikam.client_secret}"
    interval: 600

Configuration Parameters¶

Parameter	Must set	Default	Description
`tenant_id`	Yes	-	Entra ID tenant (directory) ID
`client_id`	Yes	-	Application (client) ID of the app registration
`client_secret`	Yes	-	Client secret of the app registration. A secret: reference it with `${secret:…}`, `${env:…}` or `${file:…}` rather than writing it in the file
`interval`	No	`300`	Seconds between collections

Metrics Collected¶

Overview¶

Metric	Unit	Description
`senhub.exchange_online.up`	`1`	`1` when the Microsoft 365 reporting API answered this cycle, else `0`
`senhub.exchange_online.service.health`	`1`	Exchange service-health status (Healthy=2, Degraded=1, Error/other=0), split by `senhub.exchange_online.service.display_name`

Mail Flow¶

Mail-flow metrics are cumulative counters reported over the Microsoft 365 reporting window.

Metric	Unit	Description
`senhub.exchange_online.mail.sent`	`{mail}`	Messages sent over the reporting window
`senhub.exchange_online.mail.received`	`{mail}`	Messages received over the reporting window
`senhub.exchange_online.mail.delivered`	`{mail}`	Messages delivered over the reporting window
`senhub.exchange_online.mail.failed`	`{mail}`	Messages that failed delivery over the reporting window

Mailboxes¶

Metric	Unit	Description
`senhub.exchange_online.mailboxes`	`{mailbox}`	Total number of mailboxes
`senhub.exchange_online.mailboxes.active`	`{mailbox}`	Number of active mailboxes
`senhub.exchange_online.mailbox.storage.used`	`By`	Total storage consumed across all mailboxes, in bytes
`senhub.exchange_online.mailbox.quota_exceeded`	`{mailbox}`	Mailboxes that have exceeded their warning quota

Requirements¶

An Azure AD app registration in the monitored tenant, used for client-credentials (application) authentication.
A client secret issued for that app registration (referenced via client_secret).
Application API permissions granted to the app registration, with tenant admin consent:
- Reports.Read.All — mail-flow, mailbox counts and storage from the Microsoft 365 reporting API.
- ServiceHealth.Read.All — Exchange service-health status.
Outbound HTTPS (port 443) from the agent host to the Microsoft 365 endpoints (login.microsoftonline.com and graph.microsoft.com).

Reporting API delay

The Microsoft 365 reporting API aggregates mail-flow and mailbox usage over a reporting window and publishes with a delay; values reflect the most recent window Microsoft has finalized rather than the current instant.

Outputs¶

Exchange Online metrics are available through every configured output — OTLP, Prometheus, and the pull formats (PRTG, Nagios, Web UI). For PRTG and Nagios, query the probe by its configured name:

curl "http://localhost:8080/api/{agentkey}/prtg/metrics/exchange-online"
curl "http://localhost:8080/api/{agentkey}/nagios/metrics/exchange-online"

Metric reference¶

Every metric this probe can emit. Metric is the OpenTelemetry name the OTLP, Prometheus and Zabbix outputs derive theirs from. Name is what a Nagios check and the API metrics= filter match. PRTG channel is the label PRTG shows, placeholders filled from the series' tags.

Metric	Name	PRTG channel	Unit	Description
`senhub.exchange_online.up`	`exchange_online_up`	Service Reachable	#	1 when the Microsoft 365 reporting API answered this cycle, else 0
`senhub.exchange_online.service.health`	`exchange_online_service_health`	Service Health ({service_display_name})	#	Exchange service-health status (Healthy=2, Degraded=1, Error/other=0)
`senhub.exchange_online.mail.sent`	`exchange_online_mail_sent`	Mail Sent	#	Messages sent over the reporting window
`senhub.exchange_online.mail.received`	`exchange_online_mail_received`	Mail Received	#	Messages received over the reporting window
`senhub.exchange_online.mail.delivered`	`exchange_online_mail_delivered`	Mail Delivered	#	Messages delivered over the reporting window
`senhub.exchange_online.mail.failed`	`exchange_online_mail_failed`	Mail Failed	#	Messages that failed delivery over the reporting window
`senhub.exchange_online.mailboxes`	`exchange_online_mailboxes`	Mailboxes Total	#	Total number of mailboxes
`senhub.exchange_online.mailboxes.active`	`exchange_online_mailboxes_active`	Mailboxes Active	#	Number of active mailboxes
`senhub.exchange_online.mailbox.storage.used`	`exchange_online_mailbox_storage_used`	Mailbox Storage Used	Bytes	Total storage consumed across all mailboxes
`senhub.exchange_online.mailbox.quota_exceeded`	`exchange_online_mailbox_quota_exceeded`	Mailboxes Over Quota	#	Number of mailboxes that have exceeded their warning quota