Log monitoring tools performing behavioral analysis have alerted several suspicious logins on a Linux server occuring during non-business hours. After further examination of all login activities, it i

NTP (Network Time Protocol) is the protocol used on Linux systems - typically via ntpd or chronyd - to synchronize the local clock with remote time servers. When the NTP daemon stops, the system clock drifts freely, which can cause time-based log anomalies like logins appearing outside business hours when they actually occurred during them. Correcting and restarting the NTP service resolves clock drift.

TimeKeeper is not a recognized standard network protocol for time synchronization on Linux systems.

OSPF (Open Shortest Path First) is a link-state routing protocol used for IP routing, not time synchronization.

PPP (Point-to-Point Protocol) is a data-link layer protocol used for direct connections between two nodes, not for time synchronization.