Chapter 20: Configuring Sntp; About Sntp Authentication; General Sntp Commands - Enterasys C3G124-24 Configuration Manual

This chapter describes how to use CLI commands to configure the Simple Network Time Protocol
(SNTP), which synchronizes device clocks in a network. Also included are SNTP authentication
commands.
For information about...

About SNTP Authentication

General SNTP Commands

SNTP Authentication Commands
About SNTP Authentication
The Simple Network Time Protocol (SNTP) is used to provide a precise time reference for time
critical applications. Therefore, SNTP can pose a security risk if malicious users attempt to corrupt
a SNTP timestamp to create a false time on network equipment. SNTP security mechanisms
ensure that only authorized servers are allowed to distribute time samples to the SNTP clients.
SNTP provides increased security in the form of authentication. Authentication is intended to
overcome security risks by ensuring that any response received from an SNTP time server has
come from the intended reference. The user defines a key on the switch and enables
authentication. The same key must be defined on the server in order for the switch to accept
timestamp information from the server.
The client sends a request for time to an SNTP server. The server then responds to the client with a
time sample, along with the encrypted keys configured on the SNTP server. Upon receipt of the
time sample, the client un-encrypts the key and verifies the key against the trusted key configured
on the switch for a specified SNTP server. The client can then be sure that the received time sample
was indeed transmitted from the authorized SNTP server.
SNTP utilizes MD5 authentication (Message Digest Encryption 5), which safeguards device
synchronization paths to SNTP servers. MD5 is 128-bit cryptographic hash function, which
outputs a fingerprint of the key. MD5 verifies the integrity of the communication and
authenticates the origin of the communication.
The process to configure the switch SNTP client for authentication includes these steps:
1. Configure up to five authentication keys with the "set sntp authentication-key" command
(page 20-13).
Note: A management IP (host, routing interface, or loopback) address must be configured for SNTP
to work..
20
Configuring SNTP
Refer to page...
Enterasys C3 Configuration Guide 20-1
20-1
20-2
20-12