Which type of NetScaler Service Monitor can test a three-way handshake between the NetScaler and the back-end server?

• A. Udp
• B. Ping
• C. Tcp
• D. Ldap

Answer: (C)

Testable concept here is that a three-way handshake is part of establishing a TCP connection. NetScaler’s TCP service monitor actually tries to open a TCP session to the backend on the specified port, which requires the SYN, SYN-ACK, and ACK sequence to complete. If the handshake succeeds within the timeout, the backend port is considered reachable and the service is up; if it fails, the monitor marks the service down.

UDP monitors test a connectionless path and don’t perform any handshake, so they can’t verify a proper TCP connection. Ping checks reachability via ICMP and has no interaction with a TCP port or application protocol. LDAP monitors use the LDAP protocol over a TCP (or TLS) transport but aren’t focused on testing the generic TCP handshake as a standalone test. Therefore, the type that tests the three-way TCP handshake is the TCP monitor.