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Item
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Description
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IoT card
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Per MIIT regulation (Network Security Letter [2020] No. 1173), DCDN cannot provide acceleration for IoT card devices in the Chinese mainland. These devices may fail to connect to DCDN POP IP addresses.
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Security violations
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Alibaba Cloud reviews content on all accelerated domains. Domains that cannot be accelerated by DCDN include but are not limited to:
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Domains of websites whose content is inaccessible or does not provide valid information
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Domains that point to illegal private game servers
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Domains of websites that provide multiplayer role-playing games and card games
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Domains of websites that provide unauthorized software downloads
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Domains of websites for peer-to-peer (P2P) lending
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Domains of unofficial lottery websites
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Domains of unlicensed and pharmaceutical websites
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Domains of websites that contain illicit content, such as pornography, drugs, and gambling
Note
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You are legally responsible for content on your accelerated domain. DCDN regularly reviews accelerated domains. Once DCDN detects illicit content on a domain, it immediately disables or blocks the domain. In serious cases, DCDN may permanently block all domains under the Alibaba Cloud account.
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If you add a wildcard domain such as *.example.com to DCDN and a matching domain such as a.example.com contains illicit content, DCDN disables the wildcard domain *.example.com.
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If your domain fails the review, check the rejection reason on the Domain Names page in the DCDN console, fix the content, and resubmit.
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Bandwidth/QPS throttling rules
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Per the Alibaba Cloud International Website Product Terms of Service, if you expect traffic spikes on DCDN-accelerated services, apply for burst bandwidth at least 3 business days in advance. For major events (including the Spring Festival Gala and Double 11 Global Shopping Festival), apply at least 1 month in advance.
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If approved, service availability is guaranteed within the agreed burst bandwidth level.
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If you do not apply or the application is rejected, Alibaba Cloud reserves the right to throttle bandwidth to maintain stability for other customers. Throttling is not guaranteed to occur — Alibaba Cloud decides based on service conditions and burst level. Alibaba Cloud is not responsible for reduced availability caused by these measures.
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Without an approved burst bandwidth application, the following issues may occur:
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Burst bandwidth may trigger throttling rules of DCDN. For more information, see Burst bandwidth.
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A sudden increase in QPS may trigger HTTP flood protection rules of DCDN. As a result, the domain name is added to a sandbox. For more information, see Introduction to sandboxes.
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Potential domain attacks or data transmission abuse
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By default, DCDN does not provide access control or security capabilities. If your domain is attacked or abused for data transmission, unexpected bandwidth surges may generate higher-than-expected bills.
High bills from attacks or abuse cannot be waived or refunded. To prevent such bills, see High bill risk warning.
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Shared IP addresses
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By default, DCDN assigns shared accelerated IP addresses to your domain. These IP addresses and their ports are shared across all users, so ports other than 80 and 443 may be open. Some security products may flag these non-standard open ports as vulnerabilities.
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Files
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File cache
For responses with Cache-Control directives that allow caching, DCDN can cache files up to 500 GB.
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File upload
You can upload files to origin servers through DCDN. Maximum file size: 300 MB.
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Origin fetch
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Custom HTTP request headers added via the DCDN console or API cannot exceed 300 bytes.
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Timeout
Default timeout: 10 seconds for TCP origin requests, 30 seconds for HTTP origin requests.
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Response header
If an origin server does not include Content-Type in the response, DCDN adds Content-Type:application/octet-stream automatically.
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Automatic conversion from HEAD to GET for origin requests
By default, DCDN POPs convert HEAD requests to GET before forwarding to the origin. To preserve HEAD requests, configure the following custom request header in the DCDN console. For more information, see Modify incoming request headers.
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Length of URLs and request headers
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HTTP/2:
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http2_max_field_size=32 KB (default): each individual HTTP request header or URL cannot exceed 32 KB. Otherwise, HTTP 414 is returned.
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http2_max_header_size=128 KB (default): the total length of all HTTP request headers and URLs cannot exceed 128 KB. Otherwise, HTTP 400 is returned.
HTTP/1.1: large_client_header_buffers is set to 4 buffers of 64 KB. Each individual HTTP request header or URL cannot exceed 64 KB (HTTP 414). The total of all headers and URLs cannot exceed 256 KB (HTTP 400).
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Request methods
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DCDN supports the GET, PUT, POST, HEAD, and OPTION request methods.
Note
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To support DELETE and PATCH requests, enable dynamic content acceleration.
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PUT allows requests with or without a body (Content-Length=0).
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POST supports chunked encoding and allows requests with or without a body (Content-Length=0).
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For cached static resources, POPs convert HEAD requests to GET before forwarding to the origin. For dynamic (uncached) resources, HEAD requests are forwarded as-is. To preserve HEAD requests for static resources, configure the following custom request header in the DCDN console. For more information, see Modify incoming request headers.
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API calls for each account
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Each API operation can be called up to 1,000 times per second per account. If exceeded, the following error is returned: ErrorCode:Throttling
ErrorMessage:Request was denied due to flow control.
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HTTPS-based access control
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If a client does not include Server Name Indication (SNI) during the SSL handshake with a DCDN POP, the DCDN POP cannot guarantee a successful handshake.
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