Network Time Protocol (NTP) On Cisco Devices - Part 1

Network Time Protocol (NTP) On Cisco Devices - Part 1 of 4

Cisco devices have a software clock that tracks the time. You'll want to have your devices keep accurate time across your network so that you can correlate events, especially log messages, across a network. If your devices don't maintain a consistent time, then this task becomes difficult to nearly impossible. The preferred method of maintaining consistent time across a network is with the Network Time Protocol (NTP).

NTP uses UDP port 123 to provide accurate time updates between devices. There are four versions of NTP. Cisco routers use NTPv3 by default. NTP servers use a hierarchical stratum ranking with the lower stratum being the most accurate.

Cisco devices can use NTP(v3) in three different modes: client, symmetric active, and broadcastclient . In this lesson we looked at configuring client mode.

As a last resort you can configure one of your Cisco routers to act as an NTP server.

[hiroshir]

Youtube is the shit, just came from reading a shit load stuff about NTP and IARC.