IP addresses are mainly used for remote access to your instance or the services deployed on your instance. Currently, in the classic network provided by Alibaba Cloud, IP addresses are uniformly distributed. They are divided into public and private IP addresses.
Intranet IP addresses
Each classic network-connected ECS instance is assigned with an intranet IP address.
Intranet IP addresses can be used in the following scenarios:
- Load balancing
- Mutual intranet access between ECS instances
- Mutual intranet access between ECS instances and other cloud services, such as OSS and RDS
Communication traffic through intranet IP addresses within an intranet is free of charge For more information, see Intranet.
Once a classic network-connected ECS instance is created, you cannot change its intranet IP address.
|Do not change an intranet IP address within a guest operating system. Otherwise, communication within an intranet gets interrupted.|
Public IP addresses
If you purchase bandwidth for Internet access, a public IP address is assigned to your classic network-connected ECS instance. You cannot change the public IP address once it is assigned.
A public IP address is used in the following scenarios:
- Mutual access between an ECS instance and the Internet
- Mutual Internet access between ECS instances and other Alibaba Cloud services
When you create an ECS instance, a public IP address is assigned to it if Assign public IP is selected.
For a Subscription instance with no public IP address, you can use the Upgrade Configuration or the Renew for Configuration Downgrade feature to purchase public network bandwidth.
You are billed for usage of Internet outbound traffic only. For more information, see Billing of network bandwidth.
Multicast and broadcast
Intranet IP addresses cannot be used for multicast or broadcast.