Aggregate Statistics

Count of HTTP 451 Responses

This chart shows the total number of HTTP 451 responses that were present during the last aggregate query. This chart offers a snapshot of whether the total amount of HTTP 451 codes "in the wild" is experience any significant increases or decreases. Note that the Y-axis does not start at zero, and that the dynamic scale of the graph is such that it may only encompass a range of a few hundred. Therefore, the chart may tend to over-represent the overall size of any fluctuations in the count of HTTP 451 responses.

Proportion of Selected HTTP Error Codes

Despite the HTTP 451 standard having been adopted six years ago, it has yet to be implemented at large scale. An optimistic reading of this may be that there is actually very little legal action requiring website operators to withhold content from certain reasons. The pessimistic view is that such restrictions are still taking place, but in ways that are not as readily apparent. For example, an Internet Service Provider may silently intercept requests for a certain site and return a “404 – Not Found” or “403 – Forbidden” code before the request even reaches the server. This may also mean that in cases of geoblocking, a server is still returning a 200 - OK response. Instead of a 451, the response contains a message about unavailable content rather than the content the user was seeking out, which is frequently the case when a video streaming platform restricts its content to certain regions of the world.

Interestingly, there are generally significantly more HTTP 418 codes than HTTP 451. The 418 code was introduced as part of an April Fool's RFC and describes the "HyperText Coffee Pot Control Protocol." The fact that this joke HTTP code is more widespread than HTTP 451, an actual approved standard, is further sign of how unused the 451 code really is.

Proportions of Selected HTTP Response Codes

Unsurprisingly, most responses are “200 – OK,” indicating that most public-facing HTTP servers are successfully serving content. The large number of 301 and 307 codes is also unsurprising, as these redirect codes are often used when a website operator redirects plain HTTP requests to use the more secure HTTPS version of the standard. Given the short timespan of this data and the wide fluctuation in accessible Web servers, the precise values of each code are not significant. However, what is notable is that the number of HTTP 451 codes is a whole order of magnitude less than other codes. While there are tens or hundreds of millions of HTTP servers returning 200, 301, 307, 403, 404, and 500, there are mere tens of thousands of 451 responses.

Interestingly, there are generally significantly more HTTP 418 codes than HTTP 451. The 418 code was introduced as part of an April Fool's RFC and describes the "HyperText Coffee Pot Control Protocol." The fact that this joke HTTP code is more widespread than HTTP 451, an actual approved standard, is further sign of how unused the 451 code really is.