SX20 is registered with CUCM. mode of SX20 is CUCM. CUCM is pointed to NTP server. IPPhones are showing correct time but not SX20. ntp is auto for SX20 in web configuration. when I entered IP addresss for ntp server time become ok.
So question is why SX20 not gettting time from CUCM as like IPPhones. why we need to add the ntp server ip manually even in auto mode? so what is the difference between auto and manual then?
Or should we off the NTP mode to off when registered with CUCM.
So if your endpoint is provisioned with CUCM (that means config will be pushed by CUCM) then it will take the time as configured in CUCM Date time group and in that case it will override the NTP config on endpoint and make the NTP mode as Auto. And will take the time configured in CUCM Date Time Group.
But if you have just done the SIP configuration and set the CUCM as proxy on endpoint in that case the endpoint NTP config will take preference and it will not use CUCM NTP.