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TCP

The TCP monitor checks that a specific port is open and accepting connections on a server. It’s useful for monitoring services that aren’t reachable over HTTP, like databases, mail servers, or custom services.

SettingDescriptionDefault
HostIP address or hostname
PortTCP port number443
IntervalCheck frequencyshortest your plan allows
TimeoutFixed check budget (not configurable)5s
  • Databases — PostgreSQL (5432), MySQL (3306), Redis (6379).
  • Mail servers — SMTP (25/587), IMAP (993), POP3 (995).
  • Other services — SSH (22), FTP (21), or any custom port.
Agentde-fra SYN SYN-ACK ACK → connected · 12 ms host:portdb.internal:5432 RESULT socket opened before timeout → up refused / timeout → failure (retry window) No payload is sent — only connection time is recorded.

The monitor opens a TCP connection to the given host and port. The check succeeds if the connection is established within the timeout. No data is sent after connecting — only the socket opening is tested.

TCP connection time is recorded on every check, letting you track network latency to your services over time.