FAQ overview - FAQ| Alibaba Cloud Documentation Center

This topic lists commonly asked questions about Alibaba Cloud Anti-DDoS, which provides Anti-DDoS Origin Basic, Anti-DDoS Origin Enterprise, Anti-DDoS Pro, and Anti-DDoS Premium.


Type	Question
Pre-sales FAQ	Does Alibaba Cloud provide free Anti-DDoS services? Can Anti-DDoS Pro and Anti-DDoS Premium be billed only when they are triggered to mitigate DDoS attacks? Do Anti-DDoS services have trial mitigation plans? Can Anti-DDoS services protect external servers? Can Anti-DDoS Pro and Anti-DDoS Premium protect external servers that serve a domain name registered with Alibaba Cloud? Is Internet Content Provider (ICP) filing required for domain names that require the protection of Alibaba Cloud Anti-DDoS services? What are the regions supported by Anti-DDoS services? Do Anti-DDoS Pro and Anti-DDoS Premium have limits on the number of protected domain names? Do Anti-DDoS instances support wildcard domains? What are the prerequisites for setting up protection with Anti-DDoS Premium? Does the basic protection bandwidth provided by an Anti-DDoS Pro instance indicate the maximum mitigation capacity?
FAQ for the billing of burstable protection	Are burstable protection fees charged when no attacks are detected? What is the maximum mitigation capacity if I purchase an Anti-DDoS instance with a basic protection bandwidth of 20 Gbit/s and a burstable protection bandwidth of 50 Gbit/s? What happens if the size of the DDoS attacks exceeds the burstable protection bandwidth? How burstable protection is charged if the basic protection bandwidth is 30 Gbit/s, the burstable protection bandwidth is 50 Gbit/s, and the size of the DDoS attacks is 45 Gbit/s? Can I change the burstable protection bandwidth from 100 Gbit/s to 200 Gbit/s? Can I increase the protection bandwidth anytime when the basic protection bandwidth of 30 Gbit/s provided by the Anti-DDoS Pro instance cannot meet the requirements? How is the mitigation fee calculated if a domain name has been attacked multiple times in a day? How do I prevent an Anti-DDoS Pro instance from providing burstable protection?
FAQ about Anti-DDoS Origin	Basic Can Anti-DDoS Origin Basic provide protection against SYN flood attacks? Why does Anti-DDoS Origin Basic not protect my Elastic Compute Service (ECS) instance against an attack of 20 Mbit/s? Why cannot I manually deactivate blackhole filtering for an Anti-DDoS Origin Basic instance? Why the traffic data in the Anti-DDoS Origin console differs from that in Cloud Monitor and other cloud services? What is the billing difference between unlimited protection of Anti-DDoS Origin Enterprise and burstable protection of Anti-DDoS Pro? What do I do if blackhole filtering is activated for an IP address that is protected by Anti-DDoS Origin Enterprise? What do I do if I deployed an Anti-DDoS Origin Enterprise instance in the wrong region? What do I do if the error message "The IP address does not belong to your account" is displayed when I add an IP address to Anti-DDoS Origin? Enterprise What is the billing difference between unlimited protection of Anti-DDoS Origin Enterprise and burstable protection of Anti-DDoS Pro? What do I do if blackhole filtering is activated for an IP address that is protected by Anti-DDoS Origin Enterprise? What do I do if I deployed an Anti-DDoS Origin Enterprise instance in the wrong region? When I add the IP address of a service, the system prompts that the number of IP addresses reaches the upper limit. What do I do? What do I do if the error message "The IP address does not belong to your account" is displayed when I add an IP address to Anti-DDoS Origin?
Anti-DDoS Pro and Anti-DDoS Premium FAQ	What happens if an Anti-DDoS Pro or Anti-DDoS Premium instance expires? What is the clean bandwidth of an Anti-DDoS Pro or Anti-DDoS Premium instance? What happens if the actual bandwidth exceeds the clean bandwidth of an Anti-DDoS Pro or Anti-DDoS Premium instance? Can I manually deactivate the black hole status? What are the back-to-origin CIDR blocks for Anti-DDoS Pro and Anti-DDoS Premium? Are the back-to-origin CIDR blocks of Anti-DDoS Pro and Anti-DDoS Premium automatically added to a security group? Can I use an internal IP address as the origin server IP address for an Anti-DDoS Pro or Anti-DDoS Premium instance? Does the configuration of the origin server IP address for an Anti-DDoS Pro or Anti-DDoS Premium instance take effect immediately? How do I identify which website is under attack when multiple website services are protected by an Anti-DDoS Pro or Anti-DDoS Premium instance? Do Anti-DDoS Pro and Anti-DDoS Premium support the health check feature? How is traffic distributed to multiple origin servers protected by an Anti-DDoS Pro or Anti-DDoS Premium instance? Can I configure session persistence in Anti-DDoS Pro and Anti-DDoS Premium? How does session persistence work for an Anti-DDoS Pro or Anti-DDoS Premium instance? What is the default TCP timeout period for an Anti-DDoS Pro or Anti-DDoS Premium instance? What are the default HTTP and HTTPS timeout periods for an Anti-DDoS Pro or Anti-DDoS Premium instance? Do Anti-DDoS Pro and Anti-DDoS Premium support IPv6? Do Anti-DDoS Pro and Anti-DDoS Premium support WebSocket? Does Anti-DDoS Pro or Anti-DDoS Premium support mutual HTTPS authentication? Why am I unable to access HTTPS websites by using the browsers of earlier versions or from an Android mobile client? Which SSL protocols and cipher suites are supported by Anti-DDoS Pro or Anti-DDoS Premium? What are the limits on the numbers of ports and domain names protected by an Anti-DDoS Pro or Anti-DDoS Premium instance? Why does the traffic chart show a traffic scrubbing event even though the size of the traffic received by the server does not exceed the traffic scrubbing threshold? Do Anti-DDoS Pro and Anti-DDoS Premium protect websites that use NTLM authentication?
Hot FAQ about Anti-DDoS Pro and Anti-DDoS Premium	Configuration How do I enable WebSocket? How do I configure Anti-DDoS Pro or Anti-DDoS Premium by using different Alibaba Cloud accounts? What are the proactive detection IP addresses of Anti-DDoS Pro and Anti-DDoS Premium? Service exception How do I handle the issues of slow response, high latency, and access failure on websites that are protected by an Anti-DDoS Pro or Anti-DDoS Premium instance? How do I resolve 502 errors on websites protected by Anti-DDoS Pro or Anti-DDoS Premium? How do I resolve 504 errors on websites that are protected by Anti-DDoS Pro or Anti-DDoS Premium? How do I handle the issue of slow connection establishment after I configure Anti-DDoS Pro or Anti-DDoS Premium? How do I handle the issue of slow access to services protected by an Anti-DDoS Pro or Anti-DDoS Premium instance? How do I handle the issue that session persistence cannot be implemented after I configure Anti-DDoS Pro or Anti-DDoS Premium? How do I handle the issue that I cannot ping websites protected by an Anti-DDoS Pro or Anti-DDoS Premium instance? How do I handle the issue that large files fail to upload to websites that are protected by Anti-DDoS Pro or Anti-DDoS Premium? How do I handle the issue that large files fail to upload over HTTP and HTTPS after I configure Anti-DDoS Pro or Anti-DDoS Premium? Protection analysis What are the differences between website protection and non-website protection? How do I identify the types of attacks against an Anti-DDoS Pro or Anti-DDoS Premium instance? How do I mitigate NTP-based DDoS attacks? HTTPS service What are the errors returned for HTTPS service exceptions? How do I handle the error "The specified parameter is invalid" reported when I upload an HTTPS certificate? How do I convert an HTTPS certificate to the PEM format? How do I handle HTTPS access exceptions that occur when clients do not support SNI? How do I handle the issue that HTTP status code 413 is returned for GET requests？