ITPEC FE Morning April 2023 Question 34
In a TCP/IP network, which of the following is a protocol used to match the clocks of the server and the client?
Explanation
NTP — the Network Time Protocol synchronises clients' clocks with a time server.
An NTP client exchanges timestamped messages with a server over UDP port 123, estimates the network delay and its own clock offset, and corrects its clock. Servers form a hierarchy of strata below a reference clock such as GPS or an atomic clock. Matching clocks matters for comparing logs, for authentication such as Kerberos, and for certificate validity periods.
Answer (c)
Why not others:
- •(a) ARP — finds the MAC address that belongs to an IP address on the local network.
- •(b) ICMP — carries error reports and diagnostic messages, such as the echo request and reply used by ping.
- •(d) RIP — a distance-vector routing protocol that exchanges routes measured in hop count.
Key rule: Learn each protocol by its one job: NTP for time, DNS for names, DHCP for addresses, ARP for MAC lookup, ICMP for errors and diagnostics, RIP and OSPF for routing.
Networks · AI-written, may contain errors
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