Alibaba Cloud ECS provides standard intranet NTP (Network Time Protocol) servers, which you can access from your instances. We also provide external NTP services for instances that need the Internet access.

Intranet and Internet NTP servers

To deal with leap seconds and other time adjustments, ECS provides free of charge, highly accurate, and reliable NTP service for both classic network-connected and VPC-connected instances. Among the NTP servers, the ntp.cloud.aliyuncs.com offers a globally distributed NTP service using Stratum 1 servers. See the following table for the NTP servers provided by Alibaba Cloud ECS.

Classic network intranet VPC intranet Internet
- ntp.cloud.aliyuncs.com ntp1.aliyun.com
ntp1.cloud.aliyuncs.com ntp7.cloud.aliyuncs.com ntp2.aliyun.com
ntp2.cloud.aliyuncs.com ntp8.cloud.aliyuncs.com ntp3.aliyun.com
ntp3.cloud.aliyuncs.com ntp9.cloud.aliyuncs.com ntp4.aliyun.com
ntp4.cloud.aliyuncs.com ntp10.cloud.aliyuncs.com ntp5.aliyun.com
ntp5.cloud.aliyuncs.com ntp11.cloud.aliyuncs.com ntp6.aliyun.com
ntp6.cloud.aliyuncs.com ntp12.cloud.aliyuncs.com ntp7.aliyun.com

Other public services of Alibaba Cloud ECS

See the following list for some public services provided by Alibaba Cloud ECS.

Public service Description
Public DNS: 223.5.5.5 / 223.6.6.6 Domain name: http://www.alidns.com
Open source images: https://developer.aliyun.com/mirror Update frequency: The image files are updated at everyday 02:00−04:00 (UTC+8:00), including a lot of Linux distributions and open source applications.