HTTP status codes
1. What http protocol?
HTTP协议：超文本传输协议
特点：基于TCP/IP的高级协议
默认端口号：80
基于请求/响应模型：一次请求对应一次响应
无状态的：每次请求之间相互独立，不能交互数据
2. What is the http status code?
HTTP Status Code (English: HTTP Status Code) is a 3-digit code used to indicate the response status of the web server's hypertext transfer protocol. The first number of all status codes represents one of the five states of response.
3. What are the http status codes?
1xx-Information prompt ; these status codes indicate a temporary response. The client should be prepared to receive one or more 1xx responses before receiving regular responses.
100-continue.
101-Switch protocol.
2xx-Success ; this type of status code indicates that the server successfully accepted the client request.
200-OK. The client request was successful.
201-Created.
202-Accepted.
203-Non-authoritative information.
204-No content.
205-Reset content.
206-Partial content.
3xx-Redirect ; the client browser must take more action to fulfill the request. For example, the browser may have to request a different page on the server, or repeat the request through the proxy server.
302-The object has moved.
304-Not modified.
307-Temporary redirection.
4xx-Client error ; an error occurred and there seems to be a problem with the client. For example, the client requests a page that does not exist, and the client does not provide valid authentication information.
400-Bad request.
401-Access is denied. IIS defines many different
401 errors, which indicate more specific causes of errors. These specific error codes are displayed in the browser, but not in the IIS log:
401.1-Login failed.
401.2-Server configuration caused login failure.
401.3-Unauthorized due to ACL restrictions on resources.
401.4-Filter authorization failed.
401.5-ISAPI/CGI application authorization failed.
401.7-Access is denied by the URL authorization policy on the web server. This error code is specific to IIS 6.0.
403-Access is forbidden ; IIS defines many different 403 errors, which indicate more specific reasons for the error:
403.1-Execution access is forbidden.
403.2-Read access is forbidden.
403.3-Write access is forbidden.
403.4-SSL required.
403.5-SSL 128 required.
403.6-IP address is rejected.
403.7-Client certificate required.
403.8-Site access is denied.
403.9-Too many users.
403.10-Invalid configuration.
403.11-Password change.
403.12-Access to the mapping table is denied.
403.13-The client certificate was revoked.
403.14-Rejected directory listing.
403.15-Client access permission exceeded.
403.16-Client certificate is untrusted or invalid.
403.17-The client certificate has expired or is not yet valid.
403.18-The requested URL cannot be executed in the current application pool. This error code is specific to IIS 6.0.
403.19-Cannot execute CGI for clients in this application pool. This error code is specific to IIS 6.0.
403.20-Passport login failed. This error code is specific to IIS 6.0.
404-Not found; no file or directory was found. **** (more common )
404.1-The website cannot be accessed on the requested port.
404.2-Web service extension lockout policy prevents this request.
404.3-MIME mapping policy prevents this request.
405-The HTTP verb used to access this page is not allowed (the method is not allowed)
406-The client browser does not accept the MIME type of the requested page.
407-Proxy authentication required.
412-The precondition failed.
413-The request entity is too large.
414-The request URI is too long.
415-Unsupported media type.
416-The requested range cannot be met.
417-Execution failed.
423-Locked error.
5xx-server error ; the server could not complete the request due to an error.
500-Internal server error. (more common)
500.12-The application is busy restarting on the web server.
500.13-The web server is too busy.
500.15-Direct request to Global.asa is not allowed.
500.16-UNC authorization credentials are incorrect. This error code is specific to IIS 6.0.
500.18-URL authorization store cannot be opened. This error code is specific to IIS 6.0.
500.100-Internal ASP error.
501-The header value specifies an unimplemented configuration.
502-The web server received an invalid response when used as a gateway or proxy server.
502.1-CGI application timed out.
502.2-CGI application error. application.
503-The service is unavailable. This error code is specific to IIS 6.0.
504-Gateway timed out.
505-HTTP version is not supported.