Configuring Ntp Authentication - Dell S4820T Configuration Manual

Configuring NTP Authentication

NTP authentication and the corresponding trusted key provide a reliable means of exchanging NTP
packets with trusted time sources.
NTP authentication begins when the first NTP packet is created following the configuration of keys. NTP
authentication in Dell Networking OS uses the message digest 5 (MD5) algorithm and the key is
embedded in the synchronization packet that is sent to an NTP time source.
Dell Networking OS Behavior: Dell Networking OS uses an encryption algorithm to store the
authentication key that is different from previous Dell Networking OS versions; Dell Networking OS uses
data encryption standard (DES) encryption to store the key in the startup-config when you enter the ntp
authentication-key command. Therefore, if your system boots with a startup-configuration from an
Dell Networking OS version in which you have configured ntp authentication-key, the system
cannot correctly decrypt the key and cannot authenticate the NTP packets. In this case, re-enter this
command and save the running-config to the startup-config.
To configure NTP authentication, use the following commands.
1. Enable NTP authentication.
CONFIGURATION mode
ntp authenticate
2. Set an authentication key.
CONFIGURATION mode
ntp authentication-key number md5 key
Configure the following parameters:
• number: the range is from 1 to 4294967295. This number must be the same as the number in the
ntp trusted-key command.
• key: enter a text string. This text string is encrypted.
3. Define a trusted key.
CONFIGURATION mode
ntp trusted-key number
Configure a number from 1 to 4294967295.
The number must be the same as the number used in the ntp authentication-key command.
4. Configure an NTP server.
CONFIGURATION mode
ntp server [vrf] <vrf-name> {hostname | ipv4-address |ipv6-address} [ key
keyid] [prefer] [version number]
Configure the IP address of a server and the following optional parameters:
• – vrf-name : Enter the name of the VRF through which the NTP server is reachable.
– hostname : Enter the keyword hostname to see the IP address or host name of the remote
device.
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System Time and Date