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504 errors reported when handling requests with long processing time

Last Updated: Feb 07, 2018


While attempting to handle certain POST requests, the website protected by Anti-DDoS Pro waits for a much longer time than required and returns a 504 error.


This issue is because the request needs a long processing time, which exceeds the connection threshold of Anti-DDoS Pro. As a result, Anti-DDoS Pro closes the connection. The default connection thresholds of Anti-DDoS are as follows:

  • The TCP connection timeout value is 900s.
  • The HTTP/HTTPS connection timeout value is 120s.


We recommend that you configure a heartbeat detection for requests with a long processing time. Enabling heartbeat detection can help make sure that the connection is active while you wait for a request to be handled.

Additionally, you can bypass Anti-DDoS Pro for certain requests, and have these requests directly access the backend ECS instance.

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