– For a 1-Gigabit Ethernet interface, enter the keyword GigabitEthernet then the slot/portinformation.– 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 TeraScaleand ExaScale.– For a SONET interface, enter the keyword sonet then the slot/port information.– For a 10-Gigabit Ethernet interface, enter the keyword TenGigabitEthernet then the slot/portinformation.– For a VLAN interface, enter the keyword vlan then a number from 1 to 4094.– For a 40-Gigabit Ethernet interface, enter the keyword fortyGigE then the slot/port information.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 AuthenticationNTP authentication and the corresponding trusted key provide a reliable means of exchanging NTPpackets with trusted time sources.NTP authentication begins when the first NTP packet is created following the configuration of keys. NTPauthentication in Dell Networking OS uses the message digest 5 (MD5) algorithm and the key isembedded 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 theauthentication key that is different from previous Dell Networking OS versions; Dell Networking OS usesdata encryption standard (DES) encryption to store the key in the startup-config when you enter the ntpauthentication-key command. Therefore, if your system boots with a startup-configuration from anDell Networking OS version in which you have configured ntp authentication-key, the systemcannot correctly decrypt the key and cannot authenticate the NTP packets. In this case, re-enter thiscommand and save the running-config to the startup-config.To configure NTP authentication, use the following commands.1. Enable NTP authentication.CONFIGURATION modentp authenticate2. Set an authentication key.CONFIGURATION modentp authentication-key number md5 keyConfigure the following parameters:• number: the range is from 1 to 4294967295. This number must be the same as the number in thentp trusted-key command.• key: enter a text string. This text string is encrypted.3. Define a trusted key.CONFIGURATION modentp trusted-key numberConfigure a number from 1 to 4294967295.The number must be the same as the number used in the ntp authentication-key command.System Time and Date 799
