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 loopback interface, enter the keyword loopback then a number between 0 and 16383.
– For a port channel interface, enter the keyword lag then a number from 1 to 255.
– For a 10-Gigabit Ethernet interface, enter the keyword TenGigabitEthernet then the slot/port information.
– For a 40-Gigabit Ethernet interface, enter the keyword fortyGigE then the slot/port information.
– For a port extender (PE) 1 Gigabit Ethernet interface, enter the keyword peGigE then the pe-id/pe-stack—unit-id/port-
number information. The pe-id range is from 0 to 255; the stack unit number range is from 0 to 7; and the port—ID
range is from 1 to 48.
– 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
ntp authenticate
2 Set an authentication key.
CONFIGURATION mode
ntp authentication-key number md5 key
Configure the following parameters:
System Time and Date 926