Site monitoring generates status codes in detection results when it monitors sites over a protocol. This topic describes the common status codes.

Custom status codes of CloudMonitor

Protocol Status code Description
HTTP 610 The error code returned because the connection or the Secure Sockets Layer (SSL) certificate exchange timed out. The timeout period is 30s.
HTTP 613 The error code returned because an error occurred in DNS resolution.
HTTP 615 The error code returned because expected content is not found in the response or unexpected content is found in the response.
HTTP 616 The error code returned because the authentication failed.
HTTP 611 The error code returned because the monitoring failed due to other causes.
HTTP 617

The error code returned because the maximum number of redirections was exceeded.

The detection points provided by Alibaba Cloud support a maximum of five redirections with the status codes 3XX.

The detection points provided by carriers support a maximum of two redirections with the status codes 3XX.

HTTP 703 The error code returned because the server cannot be monitored over the internal network. If you need to monitor servers over the internal network, use the availability monitoring feature. For more information, see Manage availability monitoring.
Ping 550 The error code returned because the network connection failed.
Ping 610 The error code returned because no response was returned within 2s for any of the packets that were sent.
Ping 613 The error code returned because the hostname failed to be resolved to an IP address.
Ping 703 The error code returned because the server cannot be monitored over the internal network. If you need to monitor servers over the internal network, use the availability monitoring feature. For more information, see Manage availability monitoring.
TCP 550 The error code returned because the socket failed to be opened. Generally, this error occurs when system resources are insufficient.
TCP 610 The error code returned because no response was returned or the response timed out.
TCP 611 The error code returned because the connection timed out or was rejected.
TCP 615 The error code returned because expected content is not found in the response or unexpected content is found in the response.
TCP 703 The error code returned because the server cannot be monitored over the internal network. If you need to monitor servers over the internal network, use the availability monitoring feature. For more information, see Manage availability monitoring.
UDP 550 The error code returned because the socket failed to be opened. Generally, this error occurs when system resources are insufficient.
UDP 611 The error code returned because the hostname failed to be resolved and the connection failed.
UDP 610 The error code returned because the request failed to be sent or the response failed to be received.
UDP 615 The error code returned because expected content is not found in the response or unexpected content is found in the response.
UDP 703 The error code returned because the server cannot be monitored over the internal network. If you need to monitor servers over the internal network, use the availability monitoring feature. For more information, see Manage availability monitoring.
DNS 610 The error code returned because an error occurred in DNS resolution.
DNS 613 The error code returned because the DNS query failed.
DNS 615 The error code returned because expected content is not found in the response or unexpected content is found in the response.
DNS 703 The error code returned because the server cannot be monitored over the internal network. If you need to monitor servers over the internal network, use the availability monitoring feature. For more information, see Manage availability monitoring.
SMTP 610 The error code returned because the connection timed out.
SMTP 611 The error code returned because the site failed to be accessed due to causes such as failed DNS resolution, invalid email address, or failed SMTP client initialization.
SMTP 616 The error code returned because the logon request was rejected.
SMTP 703 The error code returned because the server cannot be monitored over the internal network. If you need to monitor servers over the internal network, use the availability monitoring feature. For more information, see Manage availability monitoring.
POP3 611 The error code returned because the site failed to be accessed.
POP3 703 The error code returned because the server cannot be monitored over the internal network. If you need to monitor servers over the internal network, use the availability monitoring feature. For more information, see Manage availability monitoring.
FTP 610 The error code returned because the FTP transmission failed.
FTP 611 The error code returned because the site failed to be accessed due to other causes such as failed DNS resolution or failed TCP connection.
FTP 616 The error code returned because the logon failed.
FTP 703 The error code returned because the server cannot be monitored over the internal network. If you need to monitor servers over the internal network, use the availability monitoring feature. For more information, see Manage availability monitoring.

Common HTTP status codes

Status code Description Remarks
200 OK The status code returned because the request was successful. All status codes 2XX indicate successful requests.
300 Multiple Choices The status code returned because the server can perform multiple operations based on the request. The server selects one operation to perform based on the user agent or provides a list of operations for the user agent to choose.
301 Moved Permanently The status code returned because the requested web page was permanently moved to a new URL. If the server returns this status code in response to a GET or HEAD request, the server automatically redirects the request to the new URL. You can use this status code to notify Googlebot that a web page or a website was permanently moved to a new URL.
302 Found The status code returned because the requested web page was temporarily moved to another URL. The user agent must continue to use the original URL for future requests. The server automatically redirects the request to the new URL. This is similar to the operation performed by the server when the status code 301 is returned in response to a GET or HEAD request.
303 See Other The status code returned because the user agent must send a GET request to another URL. The server automatically redirects all requests other than the HEAD request to the new URL.
304 Not Modified The status code returned because the requested web page has not been modified since the last request. If the server returns this status code, the content of the web page is not returned in the response.
305 Use Proxy The status code returned because the requested resource must be accessed by using the proxy. If the server returns the status code, the server specifies the proxy in the response.
400 Bad Request The status code returned because the server cannot process the request due to the invalid request syntax.
401 Unauthorized The status code returned because the user agent must pass the authentication. The server may return this status code after the logon.
403 Forbidden The status code returned because the server rejected the request.
404 Not Found The status code returned because the server failed to find the requested web page. For example, the server returns this status code if the requested web page does not exist on the server.
405 Method Not Allowed The status code returned because the request method is not supported.
406 Not Acceptable The status code returned because the content of the request is not acceptable.
407 Proxy Authentication Required The status code returned because the user agent is required to use the proxy to pass the authentication. The status code 407 is similar to the status code 401. If the server returns the status code, the server specifies the proxy in the response.
408 Request Timeout The status code returned because the server timed out waiting for the request.
409 Conflict The status code returned because the request cannot be completed due to a conflict. The server returns the information about the conflict in the response. Conflicts may occur in response to a PUT request that conflicts with an earlier request. In this case, the server returns this status code and the differences between the two requests.
411 Length Required The status code returned because the server refused to accept the request that did not specify the length of the content.
412 Precondition Failed The status code returned because the server cannot meet one of the preconditions set by the user agent in the request.
413 Request Entity Too Large The status code returned because the request is larger than the server is willing or able to process.
414 Request-URI Too Long The status code returned because the URI provided was too long for the server to process.
415 Unsupported Media Type The status code returned because the request entity has a media type that the server does not support.
416 Requested Range Not Satisfiable The status code returned because the range of the requested web page is invalid.
417 Expectation Failed The status code returned because the server cannot meet the requirements of the Expect request header field.
499 Client Closed Request The status code returned because the client closed the request before the server could send a response.
500 Internal Server Error The status code returned because the request cannot be completed due to an internal server error.
501 Not Implemented The status code returned because the server does not support the feature required to complete the request. For example, the server returns this status code when the server cannot recognize the request method.
502 Bad Gateway The status code returned because the server that acts as a gateway or proxy received an invalid response from the upstream server.
503 Service Unavailable The status code returned because the server is temporally unable to handle the request due to a temporary overloading or maintenance of the server.
504 Gateway Timeout The status code returned because the server that acts as a gateway or proxy did not receive a response from the upstream server within the timeout period.
505 HTTP Version Not Supported The status code returned because the server does not support the HTTP protocol version that was used in the request.