TCP Checks

TCP monitors open a connection to a host and port to verify that the service is accepting connections.

Configuration

Field	Description	Default
Host	The hostname or IP address to connect to.	Required
Port	The port number to connect to.	Required
TLS	Whether to perform a TLS handshake after connect.	Disabled
Timeout	Maximum time to wait for the connection.	10s

How It Works

1. YipYap opens a TCP connection to the specified host and port.
2. If TLS is enabled, it performs a full TLS handshake and validates the certificate.
3. The check passes if the connection is established within the timeout period.
4. The check fails if the connection is refused, times out, or the TLS handshake fails.

Use Cases

• Verifying that a database is accepting connections (e.g. port 5432 for PostgreSQL).
• Checking that a Redis instance is reachable on port 6379.
• Monitoring an SMTP server on port 25 or 587.
• Validating that a load balancer is forwarding traffic on the expected port.

Example

Monitor a PostgreSQL instance:

• Host: db.internal.example.com
• Port: 5432
• TLS: Disabled
• Interval: 60 seconds
• Timeout: 5 seconds