TCP/UDP Endpoints

Plugin: go.d.plugin Module: portcheck

Overview

Collector for monitoring service availability and response time. It can be used to check if specific ports are open or reachable on a target system.

It supports both TCP and UDP protocols over IPv4 and IPv6 networks.

Protocol	Check Description
TCP	Attempts to establish a TCP connection to the specified ports on the target system.
UDP	Sends a 0-byte UDP packet to the specified ports on the target system and analyzes ICMP responses to determine port status.

Possible TCP statuses:

TCP Status	Description
success	Connection established successfully.
timeout	Connection timed out after waiting for configured duration.
failed	An error occurred during the connection attempt.

Possible UDP statuses:

UDP Status	Description
open/filtered	No response received within the configured timeout. This status indicates the port is either open or filtered, but the exact state cannot be determined definitively.
closed	Received an ICMP Destination Unreachable message, indicating the port is closed.

This collector is supported on all platforms.

This collector supports collecting metrics from multiple instances of this integration, including remote instances.

Default Behavior

Auto-Detection

This integration doesn't support auto-detection.

Limits

The default configuration for this integration does not impose any limits on data collection.

Performance Impact

The default configuration for this integration is not expected to impose a significant performance impact on the system.

Metrics

Metrics grouped by scope.

The scope defines the instance that the metric belongs to. An instance is uniquely identified by a set of labels.

Per TCP endpoint

These metrics refer to the TCP endpoint.

Labels:

Label	Description
host	The hostname or IP address of the target system, as specified in the configuration.
port	The TCP port being monitored, as defined in the 'ports' configuration parameter.

Metrics:

Metric	Dimensions	Unit
portcheck.status	success, failed, timeout	boolean
portcheck.state_duration	time	seconds
portcheck.latency	time	ms

Per UDP endpoint

These metrics refer to the UDP endpoint.

Labels:

Label	Description
host	The hostname or IP address of the target system, as specified in the configuration.
port	The UDP port being monitored, as defined in the 'udp_ports' configuration parameter.

Metrics:

Metric	Dimensions	Unit
portcheck.udp_port_status	open/filtered, closed	status
portcheck.udp_port_status_duration	time	seconds

Alerts

The following alerts are available:

Alert name	On metric	Description
portcheck_service_reachable	portcheck.status	TCP host ${label:host} port ${label:port} liveness status
portcheck_connection_timeouts	portcheck.status	percentage of timed-out TCP connections to host ${label:host} port ${label:port} in the last 5 minutes
portcheck_connection_fails	portcheck.status	percentage of failed TCP connections to host ${label:host} port ${label:port} in the last 5 minutes

Setup

Prerequisites

No action required.

Configuration

File

The configuration file name for this integration is go.d/portcheck.conf.

You can edit the configuration file using the edit-config script from the Netdata config directory.

cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata
sudo ./edit-config go.d/portcheck.conf

Options

The following options can be defined globally: update_every, autodetection_retry.

Config options

Name	Description	Default	Required
update_every	Data collection frequency.	5	no
autodetection_retry	Recheck interval in seconds. Zero means no recheck will be scheduled.	0	no
host	Remote host address in IPv4, IPv6 format, or DNS name.		yes
ports	Target TCP ports. Must be specified in numeric format.		no
udp_ports	Target UDP ports. Must be specified in numeric format.		no
timeout	HTTP request timeout.	2	no

Examples

Check TCP ports (IPv4)

An example configuration.

Config

jobs:
  - name: local
    host: 127.0.0.1
    ports:
      - 22
      - 23

Check TCP ports (IPv6)

An example configuration.

Config

jobs:
  - name: local
    host: "[2001:DB8::1]"
    ports:
      - 80
      - 8080

Check UDP ports (IPv4)

An example configuration.

Config

jobs:
  - name: local
    host: 127.0.0.1
    udp_ports:
      - 3120
      - 3121

Check UDP ports (IPv6)

An example configuration.

Config

jobs:
  - name: local
    host: [::1]
    udp_ports:
      - 3120
      - 3121

Multi-instance

Note: When you define multiple jobs, their names must be unique.

Multiple instances.

Config

jobs:
  - name: server1
    host: 127.0.0.1
    ports:
      - 22
      - 23

  - name: server2
    host: 203.0.113.10
    ports:
      - 22
      - 23

Troubleshooting

Debug Mode

Important: Debug mode is not supported for data collection jobs created via the UI using the Dyncfg feature.

To troubleshoot issues with the portcheck collector, run the go.d.plugin with the debug option enabled. The output should give you clues as to why the collector isn't working.

• Navigate to the plugins.d directory, usually at /usr/libexec/netdata/plugins.d/. If that's not the case on your system, open netdata.conf and look for the plugins setting under [directories].

  cd /usr/libexec/netdata/plugins.d/

• Switch to the netdata user.

  sudo -u netdata -s

• Run the go.d.plugin to debug the collector:

  ./go.d.plugin -d -m portcheck

Getting Logs

If you're encountering problems with the portcheck collector, follow these steps to retrieve logs and identify potential issues:

• Run the command specific to your system (systemd, non-systemd, or Docker container).
• Examine the output for any warnings or error messages that might indicate issues. These messages should provide clues about the root cause of the problem.

System with systemd

Use the following command to view logs generated since the last Netdata service restart:

journalctl _SYSTEMD_INVOCATION_ID="$(systemctl show --value --property=InvocationID netdata)" --namespace=netdata --grep portcheck

System without systemd

Locate the collector log file, typically at /var/log/netdata/collector.log, and use grep to filter for collector's name:

grep portcheck /var/log/netdata/collector.log

Note: This method shows logs from all restarts. Focus on the latest entries for troubleshooting current issues.

Docker Container

If your Netdata runs in a Docker container named "netdata" (replace if different), use this command:

docker logs netdata 2>&1 | grep portcheck