TCP monitoring for critical service connections

What a TCP monitor tells you

A TCP check attempts to establish a connection to a host and port. If the connection cannot be made within the expected time, the service may be unavailable, the listener may be down, or a network path may be preventing access. This is useful for services that do not expose a web page or HTTP health endpoint.

A successful connection confirms reachability from the check location; it does not prove that the application is processing requests correctly. Pair TCP checks with API monitoring or application-level tests when you need to verify an HTTP response or customer workflow.

Choose the services worth monitoring

Start with ports that support important production services, such as a public-facing service endpoint or a dependency your team is responsible for operating. Record the expected host, port, owner, and impact if it becomes unreachable. Avoid monitoring services you do not own or have permission to check.

Set a check frequency that fits the service’s importance and your team’s response capacity. Review the available plan limits before adding large groups of endpoints, and route notifications through integrations monitored by the responsible team.

Use connection alerts as an investigation starting point

If a connection check fails, confirm whether the service is listening, whether the host and port are correct, and whether a recent network or firewall change could affect reachability. Compare results across check locations where available. A single failed probe is a signal to investigate, not by itself proof of a service-wide outage.

TCP monitoring complements port monitoring and website uptime monitoring. Keep a runbook with service ownership and recovery steps, then share confirmed customer impact on a status page.