1. Introduction
Obtaining the startup IP address is the first step in integrating with HTTPDNS using the HTTP API. This step is critical for all subsequent operations. This topic describes the rationale behind using a combination of multiple IP addresses and a domain name for startup endpoints, and provides a list of these endpoints.
2. "Multiple IPs + domain name" endpoints
HTTPDNS is a foundational service for network libraries. Its availability is crucial for the network functions of your application. HTTPDNS startup endpoints use a multiple IPs + domain name fallback architecture to ensure high availability for the connection channel between the client and the scheduling server. This design leverages the technical advantages of both IP addresses and domain names.
Advantages of IP addresses:
Complete independence: Startup endpoints do not rely on the local Domain Name System (DNS). This ensures the independence of the HTTPDNS service.
Hijacking prevention: Direct access using IP addresses prevents potential hijacking threats that can occur during DNS resolution.
Redundancy: Multiple built-in IP addresses prevent single points of failure (SPOFs) and improve service accessibility.
Advantages of domain names:
Dynamic updates: Domain names allow for dynamic updates of service endpoints, even though they depend on the local DNS.
Ultimate fallback: In the rare event that all IP addresses become unavailable, you can use the domain name to remotely fetch the latest service endpoints.
Operations and Maintenance (O&M) flexibility: Service access policies can be dynamically adjusted without needing to release a new client version.
By combining the advantages of both IP addresses and domain names, the multiple IPs + domain name fallback startup endpoint pattern maximizes the availability and maintainability of the scheduling service while ensuring the independence of the HTTPDNS service.
3. List of startup endpoints
Configure your application based on the following list of HTTPDNS startup endpoints. Prioritize using the IP addresses and use the domain name as a fallback in extreme scenarios.
Dual-purpose endpoints: Startup endpoints function as both scheduling and resolution services. If a scheduling result has not been returned from a startup IP address, you can use the endpoint directly for domain name resolution. However, this is not recommended for continuous use.
Functional equivalence: All startup endpoints are functionally equivalent. Choose the endpoint closest to your clients' geographic location to ensure optimal network performance.
Multi-IP retry: If a call to the scheduling API fails, retry the request with a different startup IP address or the domain name.
Endpoints outside the Chinese mainland
Region | IPv4 endpoints | IPv6 endpoints | Domain name endpoint |
China (Hong Kong) | 47.56.234.194 47.56.119.115 | 240b:4000:f10::178 240b:4000:f10::188 | resolvers-hk.httpdns.aliyuncs.com |
Singapore | 161.117.200.122 47.74.222.190 | 240b:4000:f10::178 240b:4000:f10::188 | resolvers-sg.httpdns.aliyuncs.com |
Americas | 47.246.131.175 47.246.131.141 | 2404:2280:4000::2bb 2404:2280:4000::23e | resolvers-us.httpdns.aliyuncs.com |
Europe | 47.89.80.182 47.246.146.77 | 2404:2280:3000::176 2404:2280:3000::188 | resolvers-de.httpdns.aliyuncs.com |
4. Summary
This topic explained the design of HTTPDNS startup endpoints and provided a list of endpoints for different regions. The multiple IPs + domain name architecture avoids reliance on the local DNS and provides a fallback mechanism for extreme scenarios.
Next, use the scheduling API of a startup endpoint to obtain the IP address of the resolution service. For more information about the scheduling service API, see Scheduling service API.