F5CABR: F5 Certified Administrator, BIG-IP Recertification

SSH operates over TCP, and BIG-IP's HTTP and HTTPS monitors are designed to send HTTP-formatted requests and parse HTTP responses, which an SSH service does not provide, making them unsuitable. A UDP monitor would not properly test a TCP-based service like SSH. The TCP monitor is the appropriate choice because it establishes a TCP three-way handshake (and can optionally send/receive data) against the pool member's SSH port to confirm the service is up and accepting connections, which is the standard method for monitoring TCP-based services such as SSH when no protocol-specific monitor is configured.