CDN provides a self-diagnostic tool to help you troubleshoot URL access failure. It locates the problem by checking the DNS resolution, linkage quality, node status, origin server, and data access consistency, and offers relevant solutions.
The resource URL to be diagnosed should be an activated domain name under your account. As the bandwidth generated during the diagnosis incur charges, we recommend the diagnosed resource being no more than 200 MB in size.
If a resource URL cannot be accessed, you can initiate diagnosis through Fault Self-diagnosis in the following steps:
The first part of the report displays diagnosis information, including:
The second part gives an overview of the diagnosis process and the results of each diagnosis module. Exceptional modules are clearly identified. Diagnosis modules include:
The third part elaborates on the diagnosis results.
Information such as client IP, district/ISP, and User-Agent, referer, and request method of the initiated HTTP/HTTPS request are obtained. Without the client information, some subsequent checks cannot be conducted.
The client's DNS IP is collected and checked against the client IP, to determine whether exceptions in local DNS configuration are causing issues in scheduling requests to the optimal cache nodes.
The CNAME configuration of the domain name is obtained. The CNAME resolution of the domain name needs to be configured with the correct domain name suffixed with
*.cdn.dnsv1.com (default); otherwise, requests will be unable to reach CDN nodes.
If CNAME configuration check fails, the requests will not reach CDN nodes and subsequent diagnoses will not be conducted.
Multiple websites are checked locally to obtain the client's network status. If a website cannot be accessed due to local proxy configuration, the network linkage check will fail, and subsequent diagnoses will not be conducted.
After a client request reaches a CDN node, node information will be collected, including node IP, node district/ISP, status code returned by node, hit status, and resource MD5.
If the diagnostic report cannot help you solve the problem, please submit a ticket or contact Tencent Cloud technical support.