Users Guide

To view whether NTP is configured on the interface, use the show config command in INTERFACE mode. If
ntp disable is not listed in the show config command output, NTP is enabled. (The show config
command displays only non-default configuration information.)
Configuring a Source IP Address for NTP
Packets
By default, the source address of NTP packets is the IP address of the interface used to reach the network.
You can configure one interface’s IP address include in all NTP packets.
To configure an IP address as the source address of NTP packets, use the following command.
• Configure a source IP address for NTP packets.
CONFIGURATION mode
ntp source interface
Enter the following keywords and slot/port or number information:
• For a 1-GigabitEthernet interface, enter the keyword GigabitEthernet then the slot/port
information.
• For a 10-Gigabit Ethernet interface, enter the keyword TenGigabitEthernet then the slot/port
information.
• For a Loopback interface, enter the keyword loopback then a number from 0 to 16383.
• For a port channel interface, enter the keywords port-channel then a number.
• For a VLAN interface, enter the keyword vlan then a number from 1 to 4094.
To view the configuration, use the show running-config ntp command in EXEC privilege mode (refer to
the example in
Configuring NTP Authentication).
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
System Time and Date 988