Computer Network Security

3Supervising a Computer Network

This chapter will focus on the following topics:

• – implementing the Network Time Protocol (NTP):
  • - introduction,
  • - working,
  • - configuration of the NTP;
• – implementing the syslog protocol:
  • - introduction,
  • - working,
  • - Syslog protocol configuration;
• – implement the Simple Network Management Protocol (SNMP):
  • - introduction,
  • - working,
  • - SNMP configuration.

3.1. Introduction

The management plane includes the traffic of network surveillance protocols, in this case the Syslog and the SNMP protocols. The NTP makes it possible to synchronize the time on network elements, guaranteeing the reliability of the data of the supervised elements.

3.2. Implementing an NTP server

3.2.1. Introduction to the NTP

The Network Time Protocol or NTP makes it possible to synchronize the local clock of a component of the computer network with that of a reference server (a public time server on the Internet on an internal time source).

3.2.2. How the NTP works

3.2.2.1. The different NTP levels

There are NTP servers at different levels (or strata) that correspond to different specifications. Atomic clocks make up Stratum 0 and are directly connected to the servers on Stratum 1; these servers are only accessible to servers on Stratum 2 or Stratum 3. In addition, some of these servers are freely accessible.

Figure 3.1. The different NTP levels

3.2.2.2.