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Response Codes

access_time Updated Mar 24, 2023

What is a 200 agent response code?

The Signal Sciences agent returns a 200 response code when a request is allowed through (similar to an HTTP 200 OK response).

What is a 406 agent response code?

By default, the Signal Sciences agent returns a 406 response code when a request is blocked (similar to an HTTP 406 NOT ACCEPTABLE response). You can configure rules to return alternative custom response codes other than 406 when a request is blocked.

What is a 499 agent response code?

A 499 response code indicates the client closed the connection mid-request.

What is an HTTP 504 response code?

A 504 response code is a timeout error which indicates that the gateway did not receive a response from the user’s upstream origin in the allotted time specified.

If a client is making a request and the Cloud WAF Application Load Balance (ALB) does not receive the first header byte within 60 seconds of the TCP connection being established, the requesting client will receive a 504, while the SigSci Agent will respond with a 499. This means the requesting client, if making a longstanding request through a browser, will receive a 504 error in the browser, while the SigSci Console will show a 499 for the request.

Troubleshooting 504s correlated with 499s

The longstanding request will need to be optimized to meet the 60 second threshold. If the request cannot be optimized, reach out to our support team to explain the issue in detail and we will gladly help.

Relevant timeouts in the Cloud WAF architecture

  • The Cloud WAF agent has 60 seconds to start sending a response to the ALB
  • The Cloud WAF agent has 10 seconds to negotiate TLS with the upstream
  • The Cloud WAF agent has 30 seconds to establish an HTTP connection to the upstream

What do some response codes appear as negative numbers or a zero?

The -2, -1, and 0 response codes are error response codes that are applied to requests that weren’t processed correctly.

See the error response codes troubleshooting guide for additional information about these response codes.