Reference Guide

Source IP address
Configure one interface IP address to include in all NTP packets. The source address of NTP packets is the interface IP address
the system uses to reach the network by default.
● Configure a source IP address for NTP packets in CONFIGURATION mode.
ntp source interface
○ ethernet — Enter the keyword and node/slot/port information.
○ port-channel — Enter the keyword and number.
○ vlan — Enter the keyword and VLAN number (1 to 4093).
○ loopback — Enter the keyword and number (0 to 16383).
○ mgmt — Enter the keyword and node/slot/port information (default 1/1/1).
Configure source IP address
OS10(config)# ntp source ethernet 1/1/10
View source IP configuration
OS10(config)# do show running-configuration | grep source
ntp source ethernet1/1/1
Authentication
NTP authentication and the corresponding trusted key provide a reliable exchange of NTP packets with trusted time sources.
NTP authentication begins with the creation of the first NTP packet after key configuration. NTP authentication uses the
message digest 5 (MD5) algorithm. The key is embedded in the synchronization packet that is sent to an NTP time source.
1. Enable NTP authentication in CONFIGURATION mode.
ntp authenticate
2. Set an authentication key number and key in CONFIGURATION mode (1 to 4294967295).
ntp authentication-key number md5 key
● The number must match in the ntp trusted-key command.
● The key is an encrypted string.
3. Define a trusted key in CONFIGURATION mode (1 to 4294967295). The number must match in the ntp trusted-key
command.
ntp trusted-key number
4. Configure an NTP server in CONFIGURATION mode.
ntp server {hostname | ipv4-address | ipv6-address} [key keyid] [prefer]
● hostname — Enter the keyword to see the IP address or host name of the remote device.
● ipv4-address — Enter an IPv4 address in A.B.C.D format.
● ipv6-address — Enter an IPv6 address in nnnn:nnnn:nnnn:nnnn:nnnn:nnnn:nnnn:nnnn format (elision of zeros is
supported).
● key keyid — Enter a text string as the key exchanged between the NTP server and the client.
● prefer — Enter the keyword to set this NTP server as the preferred server.
5. Configure the NTP master and enter the stratum number that identifies the NTP server hierarchy in CONFIGURATION mode
(2 to 10, default 8).
ntp master <2–10>
System management
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