ALB instance overview

DNS name

Starting from 00:00:00 on November 15, 2024 (UTC+8), new ALB instances use upgraded domain names by default: xxx.alb.aliyuncsslb.com (Chinese mainland) and xxx.alb.aliyuncsslbintl.com (outside the Chinese mainland).

New ALB instances do not support direct DNS name access. Create a CNAME record to map your domain to the ALB DNS name.

Instance network type

You can change the network type of an ALB instance between internet-facing and internal.

Item	Internet-facing ALB instance	Internal ALB instance
Use case	Expose backend services to the internet.	Access backend services within a VPC only.
IP address allocation	Assigns an EIP and a private IP address. You can associate an Anycast EIP with an ALB instance to provide low-latency access for multi-region services.	Assigns only a private IP address.
Access method	Accessible from the internet and private networks.	Accessible from private networks only.
Diagram
Billing	Includes an instance fee, a Load Balancer Capacity Unit (LCU) fee, and internet data transfer fees (charged by EIP).	Includes only an instance fee and an LCU fee.

IP version

WAF integration

• Use service-based integration to enable WAF 3.0 protection for your ALB instance. This creates a WAF-enhanced ALB instance.

  • Supported regions:

    Area	Region
    China	China (Chengdu), China (Qingdao), China (Beijing), China (Guangzhou), China (Hangzhou), China (Ulanqab), China (Shanghai), China (Shenzhen), China (Zhangjiakou), China (Hong Kong), China (Heyuan)
    Asia Pacific	Indonesia (Jakarta), Japan (Tokyo), Malaysia (Kuala Lumpur), Philippines (Manila), Singapore, South Korea (Seoul), Thailand (Bangkok)
    Europe & Americas	Germany (Frankfurt), US (Silicon Valley), US (Virginia), Mexico
    Middle East	Saudi Arabia (Riyadh) (Operated by Partner), UAE (Dubai)

  • WAF-enabled ALB instances use the WAF 3.0 SDK integration model. If your account has a WAF 2.0 instance, you must first release the WAF 2.0 instance or migrate to WAF 3.0.

    By default, ALB does not add the X-Forwarded-Proto request header. After you release a WAF 2.0 instance, direct access to the ALB instance may cause service exceptions, such as infinite redirects, because backend servers cannot identify the original request protocol (HTTP or HTTPS). To prevent this issue, you must manually enable the X-Forwarded-Proto request header in the ALB listener settings.

  • Unsupported features: After you enable WAF protection, the following WAF features are not supported: data leakage prevention and automatic Web SDK integration for website crawler protection in Bot Management.

• Internet-facing Basic and Standard ALB instances support transparent WAF 2.0 integration. Supported regions: China (Hangzhou), China (Shanghai), China (Shenzhen), China (Chengdu), China (Beijing), and China (Zhangjiakou). Internal ALB instances do not support WAF 2.0.

Cross-zone load balancing

By default, cross-zone load balancing is enabled for ALB instances. Incoming requests are distributed to backend services deployed in all selected zones within the specified region. If you disable this feature for a server group, loads are balanced across each single zone.

Instance status