What does the 451 error mean?

Often browse the Web site or check the information of friends, I believe have encountered a lot of web page problems, such as 404 Not found,403 forbidden, and so on, these error hints have their own meaning, such as 404 on behalf of the Web page did not find, 403 for the site refused access, And now the Internet has added a 451 not found Web page does not open the new status code. So what does the 451 error mean? What is the difference between it and 403 errors, the following article on the knowledge of the popular science.

What does the 451 error mean?

451 not Found is a new Web page HTTP status error code that was officially approved by the Internet Engineering Steering Committee (IESG) as a new HTTP error code "451" to represent "official censorship for legal reasons" and denied access to the content.

451 Not Found (451 error)

Tim Bris, a former Google engineer who proposed the use of 451 code, said, "in the proposal, 451 of this code is not accessible for legal reasons, but it is also suggested that specific legal restrictions should be listed and what categories of Web sites they belong to." ”

One of the heads of the Internet Engineering Task Force (IETF), Mark Nottingham, welcomed the introduction of this error code and said "it can be used immediately." But he adds that the Internet Engineering team cannot guarantee that all network service providers will use the code when they encounter legal reasons.

What's the difference between 403 and 451 errors?

403 wrong believe many friends have encountered, and sometimes a site problems, it will show 403 errors, hint: 403 Forbidden, the page is not normal access to the prompts, as shown in the picture.

403 Forbidden

The 403 error is a common error message during Web site access, meaning that resources are not available. The server understands the customer's request, but refuses to process it. This is usually caused by a permission setting on a file or directory on the server, such as the improper access rights set by IIS or Apache.

So what's the difference between 403 and 451? First of all, they belong to the HTTP Web page status code, the former is a server permissions set improperly, resulting in access to Web page users do not have permission to access, thus prompting 403 errors. The 451 error is not a server or network cause, but the content of the access to the legal reasons for the official censorship by the Internet service providers blocked, not normal access to a hint.

Little knowledge: Other common Web page error codes:

403.1

The 403.1 error is caused by a ban on "execute" access, which can occur if you attempt to execute a CGI, ISAPI, or other executable program from the directory, but the directory does not allow you to execute the program.

403.2

The 403.2 error is caused by "read" Access being blocked. This error occurs because there is no default Web page available and directory browsing is not enabled, or the directory where the HTML page to be displayed is only marked as executable or script permission.

403.3

The 403.3 error is caused by a "write" access ban, which occurs when an attempt is made to upload a file to a directory or modify a file in the directory, but the directory does not allow write access.

403.4

The 403.4 error is caused by the requirement for SSL and you must use "https" in the address of the Web page you want to view.

403.5

The 403.5 error is due to the requirement to use a 128-bit encryption algorithm Web browser, if your browser does not support the 128-bit encryption algorithm will be the error, you can connect to the Microsoft Web site for browser upgrades.

403.6

The 403.6 error was caused by the denial of the IP address. If the server has a list of IP addresses that cannot access the site, and you use an IP address that is in the list, you will return this error message.

403.7

The 403.7 error is due to a client certificate, which is returned when the resource requiring access requires that the browser have a Secure Sockets Layer (SSL) client certificate that the server can recognize.

403.8

The 403.8 error is caused by a ban on site access, and if the server has a list of DNS names that cannot access the site, the DNS name that you use returns this information when it is in the list. Note the difference between 403.6 and 403.8 errors.

403.9

The 403.9 error is caused by too many connected users, and this error is returned because the Web server is busy and cannot process the request because of traffic overload.

403.10

The 403.10 error is an error caused by an invalid configuration that is returned when you attempt to execute a CGI, ISAPI, or other executable program from the directory, but the directory does not allow the program to execute.

403.11

The 403.11 error is due to a password change that causes the page to not be viewed.

403.12

The 403.12 error is caused by the mapper denying access. The Web page you want to view requires a valid client certificate, and your client certificate map does not have permission to access the Web site and returns the mapper's access denied error.

403.13

The 403.13 error is because the Web page that needs to be viewed requires that the client certificate used with a valid client certificate has been revoked or that the certificate has been revoked.

403.14

403.14 Error [2]

The WEB server is configured not to list the contents of this directory and to deny directory listings.

403.15

The 403.15 error is caused by too many client access licenses, and this error is returned when the server exceeds its Client Access License limit.

403.16

The 403.16 error is caused by an untrusted or invalid client certificate.

403.17

The 403.17 error is due to a client certificate that has expired or is not yet in effect.