/mcpEnsure that CUCM can communicate with the NTP server on Port 123. 1. Obtain the output of utils ntp status. The stratum level can be less than 4 on the publisher for optimal performance. • If multiple NTP servers are configured, ensure at least one server is reachable; you can see the (*) symbol against the NTP server used as a reference by CUCM. • 2. Review the syslog alarm and take action accordingly. Probable causes of syslog alarms are: The external NTP server is not reachable. • NTP stratum is higher than the acceptable limit. • The publisher is down, so the Subscriber NTP is unsynchronized. • If ntpdate -q related alerts are seen, it is possible that you have NTP version 4.2.6+ with the Kiss of Death (KoD) feature enabled. (By design, the minimum interval between burst and iburst packets sent by any client is two, which does not violate this constraint. Packets sent by other implementations that violate this constraint can be dropped and a KoD packet returned if enabled). It is recommended to disable this feature when you use that version as the NTP server for a UC product. • 3. Use this diagnosis module in order to verify the NTP server is configured. utils diagnose module ntp_reachability • utils diagnose module ntp_clock_drift • utils diagnose module ntp_stratum • 4. Enter utils ntp restart in order to restart the NTP client/server. This command is useful whenever a gross time correction needs to occur immediately or whenever external servers are still reachable and operational, but synchronization fails. Use the utils ntp status command in order to determine the operational status of external NTP servers. 5. Common Known Issues with NTP Association on CUCM Cisco bug ID CSCue18813: NTP configuration tos maxdist parameter controlled via CLI Resolution: Cisco Technical Assistance Center case can be raised in order to manually add the tos maxdist parameter in the ntp.conf file. Cisco bug ID CSCuq70611: NTP Stratum test does not validate properly with single NTP Server Fixed Version: 10.5(2.10000.005) Cisco bug ID CSCui85967: CUCM jump upgrade from 6.1.5 to 9.1.2 fails due to NTP reference missing Resolution: Jump upgrade documentation has been updated and NTP configuration is listed as on of the pre- upgrade task. Cisco bug ID CSCtw46611: NTP synch fails due to incorrect file system labelling of capture.txt Fixed Version: 8.6(2.24900.017) Cisco bug ID CSCur94973: Time sync issue betn VMHost & VM Instance during M1 migration