Server Load Balancer:ALB instance overview

DNS name

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

Newly created ALB instances do not support direct access through their DNS names. You must create a CNAME record to map your custom domain name to the DNS name of the ALB instance. This allows clients to access the ALB instance through your custom domain name.

Instance network type

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

Item	Internet-facing ALB instance	Internal ALB instance
Use case	You need to expose your backend services to the internet.	You only need to access backend services from within an Alibaba Cloud VPC.
IP address allocation	Assigns an Elastic IP Address (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

• We recommend that you enable WAF 3.0 protection for your ALB instance by using the service-based integration method. This method 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	Philippines (Manila), Indonesia (Jakarta), Japan (Tokyo), Malaysia (Kuala Lumpur), Singapore, Thailand (Bangkok), South Korea (Seoul)
    Europe & Americas	Germany (Frankfurt), US (Silicon Valley), US (Virginia), Mexico (Queretaro)
    Middle East	Saudi Arabia (Riyadh) - Operated by Partner, UAE (Dubai)

  • WAF-enabled ALB instances use the WAF 3.0 service-based architecture. If you have an existing WAF 2.0 instance, you must first release the WAF 2.0 instance or migrate it to WAF 3.0.

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

  • Unsupported features: After you enable WAF, the following WAF features are not supported: data leakage prevention and automatic Web SDK integration for the bot management feature that protects against web scraping.

• If you want to use an existing WAF 2.0 instance in your account, internet-facing Basic and Standard ALB instances support transparent integration with WAF 2.0. Supported regions: China (Hangzhou), China (Shanghai), China (Shenzhen), China (Chengdu), China (Beijing), and China (Zhangjiakou). Internal ALB instances do not support WAF 2.0 integration.

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