A technician wants to send exactly seven Internet Control Message Protocol (ICMP) echo requests to a host and inspect the replies. Which command does this?

### Why this is right The `-n` option sets the number of echo requests, so `-n 7` sends seven requests. The other options control duration, timeout, or Time to Live rather than the request count. ### The concept `ping` tests whether a destination responds to network echo requests and reports round-trip time, the time for a request to reach the destination and its reply to return. It can help distinguish a name-resolution problem from a reachability problem when you test a hostname and then an IP address. A successful response is evidence that the tested path worked for those packets. A failed response does not always prove the host is offline, because a firewall or host policy may block echo requests. The options have distinct jobs: count controls how many probes are sent, while timeout controls how long to wait for a reply. ### The other options - **`ping -t host`**: continues pinging until interrupted, rather than sending exactly seven requests. - **`ping -w 7 host`**: sets a reply timeout in milliseconds, not the request count. - **`ping -i 7 host`**: sets the Time to Live value, not the number of requests. ### Terms - **ICMP**: Internet Control Message Protocol. A network protocol that includes echo request and echo reply messages used by ping. - **Round-trip time**: The elapsed time for a packet to travel to a destination and for a response to return. - **Time to Live**: A packet field that limits how many network hops a packet can traverse. - **Firewall**: A system that permits or blocks network traffic according to rules. ### Remember For `ping`, `-n` means number of requests; `-w` means wait time.