The following tables describe the status codes of each protocol that is generated in site monitoring of CloudMonitor and the common HTTP 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 has timed out. The timeout period is 30 seconds.
613 The error code returned because an error occurred during DNS resolution.
615 The error code returned because the required content is not found in the response.
616 The error code returned because the authentication has failed.
611 The error code returned because the monitoring failed.
617
The error code returned because the maximum number of redirections is exceeded.
  • The detection points provided by Alibaba Cloud support a maximum of five redirections with the status codes 3XX.
  • The detection points provided by Internet service providers (ISPs) support a maximum of two redirections with the status codes 3XX.
703 The error code returned because the server cannot be monitored over a private network. For more information about how to monitor servers over a private network, see Create a site monitoring task.
PING 550 The error code returned because the network connection has failed.
610 The error code returned because no response is returned within 2 seconds for all packets that are sent.
613 The error code returned because the hostname cannot be parsed to an IP address.
703 The error code returned because the server cannot be monitored over a private network. For more information about how to monitor servers over a private network, see Create a site monitoring task.
TCP 550 The error code returned because the socket cannot be opened. This error occurs if all system resources are depleted.
610 The error code returned because no response is returned or the response has timed out.
611 The error code returned because the connection has timed out or is rejected.
615 The error code returned because the required content is not found in the response.
703 The error code returned because the server cannot be monitored over a private network. For more information about how to monitor servers over a private network, see Create a site monitoring task.
UDP 550 The error code returned because the socket cannot be opened. This error occurs if all system resources are depleted.
611 The error code returned because the hostname cannot be parsed and the connection has failed.
610 The error code returned because the request cannot be sent or the response failed to be received.
615 The error code returned because the required content is not found in the response.
703 The error code returned because the server cannot be monitored over a private network. For more information about how to monitor servers over a private network, see Create a site monitoring task.
DNS 610 The error code returned because an error has occurred in DNS resolution.
613 The error code returned because the DNS query has failed.
615 The error code returned because the required content is not found in the response.
703 The error code returned because the server cannot be monitored over a private network. For more information about how to monitor servers over a private network, see Create a site monitoring task.
SMTP 610 The error code returned because the connection has timed out.
611 The error code returned because the site cannot be accessed due to failed DNS resolution, an invalid email address, or failed SMTP client initialization.
616 The error code returned because the logon request is rejected.
703 The error code returned because the server cannot be monitored over a private network. For more information about how to monitor servers over a private network, see Create a site monitoring task.
POP3 611 The error code returned because the site cannot be accessed.
703 The error code returned because the server cannot be monitored over a private network. For more information about how to monitor servers over a private network, see Create a site monitoring task.
FTP 610 The error code returned because the FTP transmission failed.
611 The error code returned because the site cannot be accessed due to failed DNS resolution, an invalid email address, or failed SMTP client initialization.
616 The error code returned because the logon failed.
703 The error code returned because the server cannot be monitored over a private network. For more information about how to monitor servers over a private network, see Create a site monitoring task.

Common HTTP status codes

Status code Message Description
200 OK The status code returned because the request succeeds. All 2XX status codes 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 from.
301 Moved Permanently The status code returned because the requested web page is permanently moved to a new URL. If the server returns this status code in response to a GET or HEAD request, the server redirects the request to the new URL. You can use this status code to notify Googlebot that a web page or a website is permanently moved to a new URL.
302 Found The status code returned because the requested web page is temporarily moved to another URL. The user agent must continue to use the original URL for future requests. The server redirects the request to the new URL. This is similar to the operation that is 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 a different URL. The server redirects all requests except HEAD requests 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 a proxy. If the server returns the status code, the server specifies the proxy in the response.
307 Temporary Redirect This status code is similar to the status code 302. The status code returned because the requested resource is temporarily moved to the URL that is specified in the Location header.
308 Permanent Redirect The status code returned because the requested resource is permanently moved to the URL that is specified in the Location header.
400 Bad Request The status code returned because the server cannot process the request due to invalid request syntax.
401 Unauthorized The status code returned because the user agent must pass 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 cannot 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 a proxy to pass the authentication. The status code 407 is similar to the status code 401. If the server returns the status code 407, the server specifies the proxy in the response.
408 Request Timeout The status code returned because the server did not receive a request within the timeout period.
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. When a PUT request conflicts with the last request, the server returns this status code and the differences between the two requests.
411 Length Required The status code returned because the length of the content is not specified in the request. This status code indicates that the server denied the request.
412 Precondition Failed The status code returned because the server cannot meet one of the prerequisites that are specified by the user agent in the request.
413 Request Entity Too Large The status code returned because the size of the request exceeds the processing capacity of the server.
414 Request-URI Too Long The status code returned because the URI is too long for the server to process.
415 Unsupported Media Type The status code returned because the request entity contains a media type that the server does not support.
416 Requested Range Not Satisfiable The status code returned because the Range header 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 sent 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 a 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 temporally cannot process requests. This issue occurs due to a temporary server overload or server maintenance. In most cases, the server remains unavailable for only a short period of time.
504 Gateway Timeout The status code returned because the server that acts as a gateway or proxy does 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 is used in the request.