Topic: Computer Networks
Suppose the host firewall of a computer is configured to block all incoming ICMP packets. What could be its effect on function of TCP/IP protocol stack of the host?
- A. No effect
- B. Path MTU discovery fails
- C. Slow start fails
- D. Congestion control fails
Answer: B. Path MTU discovery fails
Explanation: Path MTU (Maximum Transmission Unit) Discovery relies on the host receiving ICMP 'Destination Unreachable - Fragmentation Needed' messages from routers along the path when a packet is too large. If all incoming ICMP packets are blocked by the firewall, the host will never receive these messages, causing Path MTU discovery to fail (potentially leading to 'black hole' connections).